@article{jagannadham_2024, title={Transient Thermoreflectance Investigation of Damping from Vibrating Dislocations in Oscillating Metal Films}, volume={7}, ISSN={["1543-1940"]}, DOI={10.1007/s11661-024-07516-3}, journal={METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE}, author={Jagannadham, K.}, year={2024}, month={Jul} }
 @article{jagannadham_2019, title={Low resistance metal contacts on MoS2 films deposited by laser physical vapor deposition}, volume={30}, ISSN={["1573-482X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85065734908&partnerID=MN8TOARS}, DOI={10.1007/s10854-019-01345-6}, number={10}, journal={JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS}, author={Jagannadham, K.}, year={2019}, month={May}, pages={10024–10029} }
 @article{jagannadham_2018, title={Initial stages of delamination of the aluminum film from silicon wafer}, volume={124}, ISSN={0947-8396 1432-0630}, url={http://dx.doi.org/10.1007/S00339-018-1984-8}, DOI={10.1007/s00339-018-1984-8}, number={8}, journal={Applied Physics A}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K.}, year={2018}, month={Jul} }
 @article{jagannadham_das_reynolds_el-masry_2018, title={Nature of electrical conduction in MoS2 films deposited by laser physical vapor deposition}, volume={29}, ISSN={0957-4522 1573-482X}, url={http://dx.doi.org/10.1007/S10854-018-9551-9}, DOI={10.1007/s10854-018-9551-9}, number={16}, journal={Journal of Materials Science: Materials in Electronics}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K. and Das, K. and Reynolds, C. L. and El-Masry, N.}, year={2018}, month={Jun}, pages={14180–14191} }
 @article{jagannadham_2018, title={Thermal Conductivity Changes Due to Degradation of Cathode Film Subjected to Charge-Discharge Cycles in a Li Ion Battery}, volume={49A}, ISSN={["1543-1940"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85047183744&partnerID=MN8TOARS}, DOI={10.1007/s11661-018-4665-5}, number={8}, journal={METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE}, author={Jagannadham, K.}, year={2018}, month={Aug}, pages={3738–3752} }
 @inproceedings{hopkins_zhao_kasichainula_reainthippayasakul_lanagan_jiang_gao_nishiguchi_fukawa_2017, place={New York}, title={Characterization of Novel Materials for Thin Flexible Power Substrates for High-Density Power Electronics}, booktitle={ASME 2017 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems collocated with the ASME 2017 Conference on Information Storage and Processing Systems : August 29-September 1, 2017, San Francisco, California, USA.}, publisher={American Society of Mechanical Engineers}, author={Hopkins, Douglas and Zhao, Xin and Kasichainula, Jag and Reainthippayasakul, Wuttichai and Lanagan, Michael T. and Jiang, Yifan and Gao, Bo and Nishiguchi, Kenji and Fukawa, Yoshi}, year={2017} }
 @article{zhao_jagannadham_reainthippayasakul_lanagan_hopkins_2017, title={Characterization of Ultra-Thin Epoxy-Resin Based Dielectric Substrate for Flexible Power Electronics Applications}, volume={2017}, ISSN={2380-4505}, url={http://dx.doi.org/10.4071/isom-2017-tp55_094}, DOI={10.4071/isom-2017-tp55_094}, abstractNote={Abstract
               Available substrate materials for power module applications has been investigated for a long time. Though Direct Bonded Copper (DBC) substrates, nowadays, have been widely applied in power electronics applications, especially power modules, due to its superior performance in mechanical ruggedness, thermal conductivity, and isolation capability. Its cost and complicated requirements during fabrication processes are always concerns in industries. At the same time, flexible electronics has become a rapidly expanding area with commercial applications including displays, medical, automotive, sensors arrays, wearable electronics, etc. This paper will initiate an investigation on a dielectric material that has potential in high power wearable electronics applications. A recently developed ultra-thin Epoxy-Resin Based Dielectric (ERBD) substrate material which is suitable for power electronic applications, is introduced. The ERBD can be fabricated with thickness as low as 80μm, with more than 5kV DC isolation capability. Its thermal conductivity is 8W/mK, higher than similar product currently available in the market. ERBD is also able to be bonded with Cu plates on both sides. In this paper, the properties of ERBD are investigated. Scanning Electron Microscope (SEM) is applied to analyze the microstructure of ERBD, and its bonding interface with Cu plates. 3-omega and Transient Thermal Reflectance methods are employed to precisely measure the thermal conductivity. Dielectric constant and loss are measured at different frequency. Simulations are applied to correct the error from the fringing effect during the measurement. The leakage current of ERBD is also measured under different voltage and temperature with DC and AC condition. Reliability tests are conducted to examine the electrical isolation and shearing strength of ERBD. The suitability of ERBD for potential flexible power electronics application is discussed based on the results from investigation of properties of the dielectric.}, number={1}, journal={International Symposium on Microelectronics}, publisher={International Microelectronics and Packaging Society (IMAPS)}, author={Zhao, Xin and Jagannadham, K. and Reainthippayasakul, Wuttichai and Lanagan, Michael T. and Hopkins, Douglas C.}, year={2017}, month={Oct}, pages={000151–000156} }
 @article{zhao_jagannadham_hopkins_2017, title={Multiphysics Performance Evaluation of Flexible Substrate Based 1.2kV SiC Half Bridge Intelligent Power Module with Stacked Dies}, volume={2017}, ISSN={2380-4505}, url={http://dx.doi.org/10.4071/isom-2017-wp22_095}, DOI={10.4071/isom-2017-wp22_095}, abstractNote={Abstract
               Wide Bandgap (WBG) power devices have become the most promising solution for power conversion systems, with the best trade-off between theoretical characteristics, real commercial availability and maturity of fabrications. Advanced packaging technology is being heavily developed to take full advantages of WBG devices, in terms of materials, mechanical design, fabrication and electrical performance optimizations. In this paper, a flexible substrate based 1.2kV SiC Half Bridge Intelligent Power Module with stacked dies is introduced. The module design is based on the concept “Power Supply in Package (PSiP)”, high functionality is integrated in the module. Together with power stages, gate driver circuits, Low Dropout Regulators (LDO), digital isolators, and bootstrap circuits are integrated in the module. An ultra-thin flexible epoxy-resin based dielectric is applied in the module as substrates, its thickness can be as low as 80μm, with 8W/mK thermal conductivity. The SiC switches are double-side solderable, with copper as topside metallization on pads. No bonding wires are applied in the SiC PSiP module. The highside and lowside SiC switches on the phase leg is stacked vertically for interconnections with low parasitic and high denstiy. This work mainly addresses performance evaluation of the PSiP SiC half bridge module by multiphysics simulations. Q3D is employed to evaluate the parasitic inductance and resistance in the module, showing that parasitic inductance is lower than 1.5nH in the design. The extracted parasitics is imported in spice circuit model, simulation results show limited ringing during switching transients. Thermal simulations are employed to compare junction temperature of power modules with DBC subtrates and flexible substrates, then to evaluate the thermal performance of the designed PSiP SiC model with stacked dies. It shows that junction temperature of designed IPM is higher than regular module at same condition. The paper also provides guideline for optimized heat sink design to lower junction temperature of the SiC IPM. Mechanical simulations are employed to evaluate the pre-stress induced in modules with DBC substrate and flexible dielectric substrate, and proves that mechanical stress induced by reflowing process can be reduced significantly by using ultra-thin flexible dielectric as substrate.}, number={1}, journal={International Symposium on Microelectronics}, publisher={International Microelectronics and Packaging Society (IMAPS)}, author={Zhao, Xin and Jagannadham, K. and Hopkins, Douglas C.}, year={2017}, month={Oct}, pages={000353–000359} }
 @article{jagannadham_2017, title={The Influence of a TiN Film on the Electronic Contribution to the Thermal Conductivity of a TiC Film in a TiN-TiC Layer System}, volume={49}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/S11661-017-4401-6}, DOI={10.1007/s11661-017-4401-6}, number={1}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Nature}, author={Jagannadham, K.}, year={2017}, month={Nov}, pages={346–355} }
 @article{jagannadham_2016, title={Adhesion, Modulus and Thermal Conductivity of Porous Epoxy Film on Silicon Wafers}, volume={45}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/S11664-016-4793-X}, DOI={10.1007/s11664-016-4793-x}, number={11}, journal={Journal of Electronic Materials}, publisher={Springer Nature}, author={Jagannadham, K.}, year={2016}, month={Jul}, pages={5877–5884} }
 @article{jagannadham_2016, title={Effect of intermetallic compounds on the thermal conductivity of Ti-Cu composites}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84954128919&partnerID=MN8TOARS}, DOI={10.1116/1.4939142}, abstractNote={Ti films were deposited by magnetron sputtering on polycrystalline Cu substrates. The samples were annealed at different temperatures and characterized by x-ray diffraction for phase identification, scanning electron microscopy, and energy dispersive spectrometry for microstructure and composition and transient thermoreflectance for thermal conductivity and interface thermal conductance. The results showed that the diffused layer of Ti in Cu contained intermetallic compounds and solid solution of Ti in Cu. The thermal conductivity of the diffused layer is reduced, and the thickness increased for higher annealing temperature. The interface thermal conductance also decreased for higher temperature of annealing. A stable Cu4Ti phase was formed after annealing at 725 °C with thermal conductivity of 10 W m−1 K−1. The interface thermal conductance between the intermetallic compound and the solid solution of Ti in Cu also was reduced to 30 MW m−2 K−1. The effective thermal resistance of the diffused layer and the interface was found to increase for higher annealing temperature.}, number={2}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K.}, year={2016} }
 @inbook{jagannadham_2016, title={Electrical and thermal conductivity of indium-graphene and copper-graphene composites}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85052463875&partnerID=MN8TOARS}, booktitle={Graphene Science Handbook: Electrical and Optical Properties}, author={Jagannadham, K.}, year={2016}, pages={639–653} }
 @article{jagannadham_cui_zhu_2016, title={Substrate Effects on Growth of MoS2 Film by Laser Physical Vapor Deposition on Sapphire, Si and Graphene (on Cu)}, volume={46}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/S11664-016-5060-X}, DOI={10.1007/s11664-016-5060-x}, number={2}, journal={Journal of Electronic Materials}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K. and Cui, J. and Zhu, Y.}, year={2016}, month={Oct}, pages={1010–1021} }
 @article{zhao_jagannadham_reainthippayasakul_lanagan_hopkins_2016, title={Thermal and Electrical Characterizations of Ultra-Thin Flexible 3YSZ Ceramic for Electronic Packaging Applications}, volume={2016}, ISSN={2380-4505}, url={http://dx.doi.org/10.4071/isom-2016-THA13}, DOI={10.4071/isom-2016-THA13}, abstractNote={Abstract
               This paper presents thermal and electrical characterizations of an ultra-thin flexible 3YSZ (3 mol% Yttria Stabilized Zirconia) ceramic substrate to explore its potential for electronic packaging applications. The thicknesses of the ultra-thin 3YSZ substrates were 20 μm and 40 μm. The flexible thin ceramic substrate can provide not only better modulus for higher robustness in manufacturing, especially in Z-axis direction of modules, but also low thermal resistance for high density 2D (two dimensional) / 3D (three dimensional) power module packaging applications. To better understand the thermal and electrical properties of the ultra-thin flexible ceramic, different measurements were employed. Thermal conductivity was measured at different temperatures by 3-omega method, the results were verified by thermo-reflectance measurement at room temperature. Relative permittivity was measured from 100 Hz to 10 MHz, with dielectric losses determined by dielectric spectroscopy. The dielectric breakdown of the ultra-thin flexible 3YSZ was measured, from room temperature to 150 °C. Weibull analysis was performed on 20 measurements for each temperature. The test results showed that the thermal conductivity of 3YSZ decreased from 3.3 W/mK at 235 K to 2.2 W/Mk at 600 K. The relative permittivity decreased from 30.9 to 27.3 for higher frequencies for both substrates with different thickness. The temperature-dependence of relative permittivity and dielectric loss was studied. The results showed that these two parameters increased slowly from −65 °C to 150 °C, but more repidly from 175 °C to 250 °C. The dielectric breakdown decreased at higher temperature, from 5.76 kV to 2.64 kV for thickness of 20 μm, 7.84 kV to 3.36 kV for thickness of 40 μm. SEM (Scanning Electron Microscopy), EDS (Energy-dispersive X-ray Spectroscopy) and XRD (X-ray Powder Diffraction) analysis was performed to compare the microstructure of 3YSZ ultra-thin substrate and that of AlN (Aluminum Nitride) substrate. The microstructure of 3YSZ consisted of smaller round particles and that of AlN contained larger columnar particles. FEA (Finite Element Analysis) simulations were also applied to demonstrate the thermal properties of 3YSZ in simplified model of power modules. Though the measurement results showed that it did not meet expectations for high temperature power modules, the present work showed potential applications of the ultra-thin 3YSZ substrates in low voltage power modules, LED modules.}, number={1}, journal={International Symposium on Microelectronics}, publisher={International Microelectronics and Packaging Society (IMAPS)}, author={Zhao, Xin and Jagannadham, K. and Reainthippayasakul, Wuttichai and Lanagan, Michael. T. and Hopkins, Douglas C.}, year={2016}, month={Oct}, pages={000391–000396} }
 @article{jagannadham_2016, title={Thermal conductivity and interface thermal conductance of thin films in Li ion batteries}, volume={327}, ISSN={0378-7753}, url={http://dx.doi.org/10.1016/J.JPOWSOUR.2016.07.098}, DOI={10.1016/j.jpowsour.2016.07.098}, abstractNote={Laser physical vapor deposition is used to deposit thin films of lithium phosphorous oxynitride in nitrogen and lithium nickel manganese oxide in oxygen ambient on Si substrate. LIPON film is also deposited on LiNiMnO film that is deposited on Si. Graphene films consisting of graphene platelets are deposited on Si substrate from a suspension in isopropyl alcohol. Li-graphene films are obtained after Li adsorption by immersion in LiCl solution and further drying. Transient thermo reflectance signal is used to determine the cross-plane thermal conductivity of different layers and interface thermal conductance of the interfaces. The results show that LIPON film with lower thermal conductivity is a thermal barrier. The interface thermal conductance between LIPON and Au or Si is found to be very low. Thermal conductivity of LiNiMnO is found to be reasonably high so that it is not a barrier to thermal transport. Film with graphene platelets shows a higher value and Li adsorbed graphene film shows a much higher value of cross-plane thermal conductivity. The value of interface thermal conductance between graphene and Au or Si (100) substrate is also much lower. The implications of the results for the thermal transport in thin film Li batteries are discussed.}, journal={Journal of Power Sources}, publisher={Elsevier BV}, author={Jagannadham, K.}, year={2016}, month={Sep}, pages={565–572} }
 @article{jagannadham_2015, title={Thermal Conductivity Changes in Titanium-Graphene Composite upon Annealing}, volume={47}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/S11661-015-3259-8}, DOI={10.1007/s11661-015-3259-8}, number={2}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, Kasichainula}, year={2015}, month={Dec}, pages={907–915} }
 @article{brown_jagannadham_2015, title={Thermal Conductivity of MWNT–Epoxy Composites by Transient Thermoreflectance}, volume={44}, ISSN={0361-5235 1543-186X}, url={http://dx.doi.org/10.1007/S11664-015-3669-9}, DOI={10.1007/s11664-015-3669-9}, number={8}, journal={Journal of Electronic Materials}, publisher={Springer Science and Business Media LLC}, author={Brown, M. and Jagannadham, K.}, year={2015}, month={Feb}, pages={2624–2630} }
 @article{jagannadham_2016, title={Thermal conductivity and interface thermal conductance of titanium silicide films on Si}, volume={63}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84959478856&partnerID=MN8TOARS}, DOI={10.1109/TED.2015.2501025}, abstractNote={Titanium silicide films were prepared by magnetron sputtering of Ti on B-doped Si (100) and annealing at different temperatures up to 700 °C in argon atmosphere. Films were also prepared by laser physical vapor deposition (LPVD) of Ti at 500 °C and 600 °C on B-doped Si (100) followed by in situ annealing. The films were characterized by X-ray diffraction for phase identification, scanning electron microscopy for interface microstructure and oxygen level, atomic force microscopy for interface roughness, transient thermoreflectance for thermal conductivity and interface thermal conductance of the interface with Si. Annealing at 700 °C for 1 h was responsible for the complete formation of C54 phase. LPVD at 500 °C and 600 °C was responsible for C54 formation with smaller grain size, but unreacted Ti and other silicide phases were also present. The interface in all the films was continuous with the absence of voids. The thermal conductivity of the films increased for higher processing temperature. The interface thermal conductance for films prepared below 700 °C was lower. Film annealed at 700 °C significantly showed higher interface thermal conductance and lower effective thermal resistance. Comparison of thermal properties of the TiSi2 films with that of WSi2 films prepared previously showed that the effective thermal resistance of the C54 phase is lower.}, number={1}, journal={IEEE Transactions on Electron Devices}, author={Jagannadham, K.}, year={2016}, pages={432–438} }
 @article{jagannadham_2015, title={Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering}, volume={33}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84929008663&partnerID=MN8TOARS}, DOI={10.1116/1.4919067}, abstractNote={Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600 °C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600 °C. TiN film deposited at 600 °C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600 °C on Si(111) wafer but the film deposited at 500 °C showed cubic CrN and hexagonal Cr2N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600 °C. Nitride film of tungsten deposited at 600 °C on Si(100) wafer was nitrogen deficient, contained both cubic W2N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500 °C were nonstoichiometric and contained cubic W2N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600 °C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.}, number={3}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K.}, year={2015} }
 @article{jagannadham_2014, title={Determination of Modulus of Metal Films Using Thermoreflectance}, volume={46}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/S11661-014-2598-1}, DOI={10.1007/s11661-014-2598-1}, number={1}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K.}, year={2014}, month={Oct}, pages={229–234} }
 @article{jagannadham_2014, title={Effect of interfacial interactions on the thermal conductivity and interfacial thermal conductance in tungsten-graphene layered structure}, volume={32}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84904730005&partnerID=MN8TOARS}, DOI={10.1116/1.4890576}, abstractNote={Graphene film was deposited by microwave plasma assisted deposition on polished oxygen free high conductivity copper foils. Tungsten–graphene layered film was formed by deposition of tungsten film by magnetron sputtering on the graphene covered copper foils. Tungsten film was also deposited directly on copper foil without graphene as the intermediate film. The tungsten–graphene–copper samples were heated at different temperatures up to 900 °C in argon atmosphere to form an interfacial tungsten carbide film. Tungsten film deposited on thicker graphene platelets dispersed on silicon wafer was also heated at 900 °C to identify the formation of tungsten carbide film by reaction of tungsten with graphene platelets. The films were characterized by scanning electron microscopy, Raman spectroscopy, and x-ray diffraction. It was found that tungsten carbide film formed at the interface upon heating only above 650 °C. Transient thermoreflectance signal from the tungsten film surface on the samples was collected and modeled using one-dimensional heat equation. The experimental and modeled results showed that the presence of graphene at the interface reduced the cross-plane effective thermal conductivity and the interfacial thermal conductance of the layer structure. Heating at 650 and 900 °C in argon further reduced the cross-plane thermal conductivity and interface thermal conductance as a result of formation nanocrystalline tungsten carbide at the interface leading to separation and formation of voids. The present results emphasize that interfacial interactions between graphene and carbide forming bcc and hcp elements will reduce the cross-plane effective thermal conductivity in composites.}, number={5}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K.}, year={2014} }
 @article{zheng_jagannadham_2014, title={Interface thermal conductance between metal films and copper}, volume={45}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84899084711&partnerID=MN8TOARS}, DOI={10.1007/s11661-014-2194-4}, number={5}, journal={Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science}, author={Zheng, H. and Jagannadham, K.}, year={2014}, pages={2480–2486} }
 @article{zheng_jagannadham_2014, title={Self heating in Si<inf>0.5</inf>Ge<inf>0.5</inf>/Si and GaAs/Si thin film device structures}, volume={99}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903202733&partnerID=MN8TOARS}, DOI={10.1016/j.sse.2014.05.008}, abstractNote={Si0.5Ge0.5 and GaAs films grown on Si substrates were used to measure the interface thermal conductance between the films and the substrate. Transient thermoreflectance technique was used with the one-dimensional heat equation to simulate the experimental results. The results showed that the interface thermal conductance of SiGe/Si interface is 100 MW m−2 K−1 and that of GaAs/Si is 20 MW m−2 K−1. These values of interface thermal conductance combined with the thermal conductivity of the films were used to conclude that SiGe films are less susceptible to self heating than GaAs films of same thickness.}, journal={Solid-State Electronics}, author={Zheng, H. and Jagannadham, K.}, year={2014}, pages={41–44} }
 @article{jagannadham_2014, title={Thermal conductivity and interface thermal conductance in films of tungsten-tungsten silicide on Si}, volume={61}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84901307626&partnerID=MN8TOARS}, DOI={10.1109/TED.2014.2318281}, abstractNote={Samples of tungsten film deposited on Si substrate at room temperature by magnetron sputtering were annealed at different temperatures up to 900 °C in argon atmosphere. X-ray diffraction and scanning electron microscopy were used to follow the changes in the film and determine the formation of WSi2 phase along the interface. The formation of WSi2 phase has been detected in the sample annealed at 675 °C and above. Polycrystalline WSi2 was found to form upon annealing at 900 °C. Thermal conductivity and interface thermal conductance of the film in the as deposited and annealed condition was studied by transient thermoreflectance from the tungsten film. The variation of thermoreflectance signal with time was modeled using 1-D thermal diffusion equation. The results showed that the thermal conductivity of the film is improved but the interface thermal conductance is reduced upon annealing at higher temperature. Voids generated by the formation of WSi2 along the interface and incomplete thermal contact between the different regions in the film and the Si substrate are shown to be responsible for the lower interface thermal conductance. It is concluded that growth of epitaxial silicide on Si with good thermal contact will help reduce the thermal resistance in the devices.}, number={6}, journal={IEEE Transactions on Electron Devices}, author={Jagannadham, K.}, year={2014}, pages={1950–1955} }
 @article{jagannadham_verghese_butler_2014, title={Thermal conductivity changes upon neutron transmutation of B-10 doped diamond}, volume={116}, ISSN={["1089-7550"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84906861630&partnerID=MN8TOARS}, DOI={10.1063/1.4892888}, abstractNote={10B doped p-type diamond samples were subjected to neutron transmutation reaction using thermal neutron flux of 0.9 × 1013 cm−2 s−1 and fast neutron flux of 0.09 × 1013 cm−2 s−1. Another sample of epilayer grown on type IIa (110) single crystal diamond substrate was subjected to equal thermal and fast neutron flux of 1014 cm−2 s−1. The defects in the diamond samples were previously characterized by different methods. In the present work, thermal conductivity of these diamond samples was determined at room temperature by transient thermoreflectance method. The thermal conductivity change in the samples as a function of neutron fluence is explained by the phonon scattering from the point defects and disordered regions. The thermal conductivity of the diamond samples decreased more rapidly initially and less rapidly for larger neutron fluence. In addition, the thermal conductivity in type IIb diamond decreased less rapidly with thermal neutron fluence compared to the decrease in type IIa diamond subjected to fast neutron fluence. It is concluded that the rate of production of defects during transmutation reaction is slower when thermal neutrons are used. The thermal conductivity of epilayer of diamond subjected to high thermal and fast neutron fluence is associated with the covalent carbon network in the composite structure consisting of disordered carbon and sp2 bonded nanocrystalline regions.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={Jagannadham, K. and Verghese, K. and Butler, J. E.}, year={2014}, month={Aug} }
 @article{zheng_jagannadham_2013, title={Influence of dopants on the thermal conductance of GaN-sapphire interface}, volume={60}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84878158518&partnerID=MN8TOARS}, DOI={10.1109/TED.2013.2257174}, abstractNote={Transient thermoreflectance (TTR) was used to characterize the interface thermal conductance (h) between GaN and sapphire at room temperature. Undoped, n-type, and p-type GaN films are grown by metal-organic chemical vapor deposition (MOCVD) on (0001) sapphire substrate. An In film pressed onto the GaN surface is used as a transducer and to measure the TTR signal. The TTR signal is also used to characterize the attenuation of acoustic waves and the surface roughness of the sapphire wafer. Results are modeled using 1-D heat conduction, and the value of h is determined. Results indicate that the value of h of the In-GaN interface remains between 18 and 28 MWm-2K-1. The value of h for the interface between undoped or n-type GaN and sapphire is low at 8 MWm-2K-1, and that between p-type GaN and sapphire is lower at 3 MWm-2K-1. The absence of good atomic level contact between pressed In and GaN is considered responsible for the low value of h. High concentration of Mg dopant atoms in the p-type GaN films at the interface, sapphire wafer with rough surface, and high dislocation density are also considered responsible for the lower value of h. The results indicate poor thermal energy dissipation, higher device temperature, reduced transconductance, and related device performance.}, number={6}, journal={IEEE Transactions on Electron Devices}, author={Zheng, H. and Jagannadham, K.}, year={2013}, pages={1911–1915} }
 @article{zheng_jagannadham_2013, title={Influence of laser irradiation and microwave plasma treatment on the thermal properties of graphene platelets}, volume={31}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84880166711&partnerID=MN8TOARS}, DOI={10.1116/1.4809581}, abstractNote={Graphene platelets synthesized by chemical exfoliation were deposited to form a film on Cu substrate. Samples of the film of graphene platelets were subjected to laser irradiation with wavelength 266 nm, pulse duration 6 ns from Nd-YAG laser at repetition of 10 Hz. Microwave hydrogen plasma treatment was also used for 300 s and 600 s to modify the film of graphene platelets on another set of samples. Raman spectroscopy on the film before and after these different treatments indicated that the crystallite size is reduced and defect density is increased. The samples coated with Au film and pressed with In film on the surface were used to determine the transient thermo reflectance from the surface upon incidence of Nd-YAG laser beam with wavelength 532 nm. Numerical analysis of the variation of thermo reflectance signal with time was used to evaluate the laser or plasma induced changes in the thermal conductivity of graphene film and the interface thermal conductance between Au and graphene. The results showed that the thermal conductivity of graphene platelet film is reduced although the interface thermal conductance is improved. The reduction in thermal conductivity of graphene platelets is explained by the decrease in the crystallite size and increase in defect density. The increase in the interface thermal conductance is also explained to arise from smoothening of the graphene platelet film surface and improvement in the contact between Au and graphene and graphene and Cu induced by laser or microwave plasma irradiation.}, number={4}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Zheng, H. and Jagannadham, K.}, year={2013} }
 @article{zheng_jagannadham_youssef_2014, title={Thermal conductivity of exfoliated p-type bismuth antimony telluride}, volume={43}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84897599427&partnerID=MN8TOARS}, DOI={10.1007/s11664-013-2813-7}, number={2}, journal={Journal of Electronic Materials}, author={Zheng, H. and Jagannadham, K. and Youssef, K.}, year={2014}, pages={320–328} }
 @article{zheng_jagannadham_2013, title={Transient thermoreflectance from graphene composites with matrix of indium and copper}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84875827948&partnerID=MN8TOARS}, DOI={10.1063/1.4794801}, abstractNote={Transient thermoreflectance was measured from In and In-graphene composite films pressed on to different substrates that include Si, GaAs, Cu and Cu-graphene composite. Measurements were also made from Al film deposited on substrates of Cu and Cu-graphene composite. The experimental results were modeled using solution to the thermal diffusion equation to determine the thermal conductivity of the phases and thermal conductance of the interface. The In-graphene and Cu-graphene composites are found to spread the heat more rapidly than In and Cu, respectively. The interface thermal conductance of In or In-graphene film pressed on to Cu was found to be smaller than the observed values for metal-metal contacts reported in the literature although higher than the value observed for the interface between Pb-Sn eutectic solder alloy bonded to Cu. The interface thermal conductance between Al film deposited on mechanically polished Cu or Cu-graphene composite is also found to be much lower than the value observed previously. The smaller value of interface thermal conductance of either In or In-gr or Al film on different substrates is explained by absence of atomic level bonding, presence of rough surfaces with incomplete contact and oxygen or water vapor at the interface.}, number={3}, journal={AIP Advances}, author={Zheng, H. and Jagannadham, K.}, year={2013} }
 @article{jagannadham_2012, title={Electrical conductivity of copper–graphene composite films synthesized by electrochemical deposition with exfoliated graphene platelets}, volume={30}, ISSN={2166-2746 2166-2754}, url={http://dx.doi.org/10.1116/1.3701701}, DOI={10.1116/1.3701701}, abstractNote={Films of graphene/copper composite in copper matrix were deposited on copper foil using an aqueous electrolyte solution of 0.2 M CuSO4 containing graphene oxide suspension at a low current density of 1.75 mA cm−2. Graphene oxide is reduced by further heating the samples in flowing hydrogen atmosphere maintained at 20 Torr and 400 °C for 3 h. The composite samples with different thickness, between 365 and 515 μm, deposited on a Cu foil of thickness 135 μm were characterized for graphene structure, morphology, and distribution. Electrical resistivity and temperature coefficient of electrical resistance of the samples at 300 K were measured using a four-probe method. The results were used to determine the electrical resistivity and temperature coefficient of resistance of the composite layers. The volume fraction and resistivity of graphene were evaluated using effective mean field analysis of the resistivity and temperature coefficient of resistance of the composite films. The results illustrate that the resistivity of graphene is much lower than that of copper and copper–graphene composite films are favorable for electrofriction applications.}, number={3}, journal={Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena}, publisher={American Vacuum Society}, author={Jagannadham, Kasichainula}, year={2012}, month={May}, pages={03D109} }
 @article{brown_jagannadham_2013, title={Interfacial effects in the electrical conductivity and viscous deformation of multiwall carbon nanotube-epoxy composites prepared by sonication}, volume={47}, ISSN={["1530-793X"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84889037322&partnerID=MN8TOARS}, DOI={10.1177/0021998312466119}, abstractNote={ Multiwall carbon nanotube composites with epoxy matrix were prepared by sonication followed by long curing. The electrical conductivity of the composite samples was measured and found to follow percolation behavior with low threshold mass fraction of multiwall carbon nanotubes and smaller value of critical exponent. The lower values of threshold and exponent are associated with higher purity and better interfacial contact between the multiwall carbon nanotubes and with the epoxy. The temperature dependence of electrical conductivity showed that both variable range hopping and fluctuation-induced tunneling mechanisms are followed. The dependence of conductivity on the width of the epoxy barrier film between multiwall carbon nanotubes is used to establish that fluctuation-induced tunneling through interfacial regions is the appropriate mechanism of conduction in the composites. The activation energy for viscous deformation of the composites was evaluated using dynamic mechanical analysis and found to increase for higher mass fraction of multiwall carbon nanotubes in the composite. These results indicate that interfacial interaction is significant in the molecular movement in the epoxy. }, number={27}, journal={JOURNAL OF COMPOSITE MATERIALS}, author={Brown, M. and Jagannadham, K.}, year={2013}, month={Dec}, pages={3413–3420} }
 @article{jagannadham_2013, title={Volume fraction of graphene platelets in copper-graphene composites}, volume={44}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84872005130&partnerID=MN8TOARS}, DOI={10.1007/s11661-012-1387-y}, number={1}, journal={Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science}, author={Jagannadham, K.}, year={2013}, pages={552–559} }
 @article{jagannadham_2011, title={Influence of laser and thermal treatment on the thermal conductivity of In-graphene composites}, volume={110}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-81355142160&partnerID=MN8TOARS}, DOI={10.1063/1.3662181}, abstractNote={Graphene processed by thermal, laser, and thermal plus laser treatments was used to synthesize the indium-graphene composite foils. The symmetric nature of the G’ band in the Raman spectrum was used to identify that the graphene was only few layers thick. Quantitative image analysis was used to determine the volume fraction of graphene. Electrical resistivity and temperature coefficient of resistance of the composite coupled with effective mean field approximation were analyzed to determine the volume fraction and resistivity of graphene. Thermal conductivity of the composite foils was measured using the three-omega method and multilayer analysis. The thermal conductivity of In-gr foils prepared by the three methods of processing graphene was found to be 1.8 W/cm.K. The results indicate that the improvement in the thermal conductivity of the composites was same by the three methods of treatment of graphene.}, number={9}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={2011} }
 @article{jagannadham_2011, title={Orientation dependence of thermal conductivity in copper-graphene composites}, volume={110}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-80055001458&partnerID=MN8TOARS}, DOI={10.1063/1.3641640}, abstractNote={Copper and graphene multilayer films were deposited on a copper substrate. The surface of the multilayer film was covered with another film of copper by electrochemical deposition. An electrically insulating film of polymer followed by films of silicon and yttria-stabilized zirconia were deposited to isolate the sample electrically from a gold heater line deposited on the top. The three-omega method was used to determine the cross-plane thermal conductivity in the sample. The effective planar thermal conductivity in the sample was determined from two gold heater lines deposited adjacent to each other on the surface. The gradient of temperature between the heater lines was evaluated under steady state to determine the planar thermal conductivity. The results show that the cross-plane thermal conductivity in the copper-graphene layers is reduced as a result of the lower thermal conductivity normal to the graphene planes. The planar thermal conductivity in the copper-graphene layers was not reduced below that in copper. The interface thermal resistance between copper and graphene was evaluated from the planar thermal conductivity. The interface thermal resistance either in the cross plane direction or in the planar direction is found to be not a limiting factor for the improvement in the thermal conductivity in the copper-graphene composite films.}, number={7}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={2011} }
 @article{jagannadham_2012, title={Thermal conductivity of copper-graphene composite films synthesized by electrochemical deposition with exfoliated graphene platelets}, volume={43}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84861800394&partnerID=MN8TOARS}, DOI={10.1007/s11663-011-9597-z}, number={2}, journal={Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science}, author={Jagannadham, K.}, year={2012}, pages={316–324} }
 @article{jagannadham_2010, title={A connection between continuum and atomic description of interface thermal conductance}, volume={108}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78149460680&partnerID=MN8TOARS}, DOI={10.1063/1.3499625}, abstractNote={A continuous distribution of thermal sources is used in the two phases at the interface to satisfy the boundary conditions associated with thermal conduction in a two-phase medium. The distribution of thermal sources is used to determine the temperature profile when there is an external source of thermal energy in phase 1 or when there is a step in the temperature at the interface due to finite interface thermal conductance. The thermal sources are identified with phonons present at the interface. The phonon distributions are superimposed to arrive at the temperature profile in a two-phase medium with an external source and finite interface thermal conductance. The interface thermal conductance is related to the variation in phonon distributions. Interface thermal conductance of Si/Ge interface determined from the present model is close to the value predicted by acoustic mismatch and diffuse mismatch models.}, number={8}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={2010} }
 @article{sruti_jagannadham_2010, title={Electrical conductivity of graphene composites with in and In-Ga alloy}, volume={39}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77954622457&partnerID=MN8TOARS}, DOI={10.1007/s11664-010-1208-2}, number={8}, journal={Journal of Electronic Materials}, author={Sruti, A.N. and Jagannadham, K.}, year={2010}, pages={1268–1276} }
 @article{jagannadham_lance_butler_2011, title={Laser annealing of neutron irradiated boron-10 isotope doped diamond}, volume={46}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79751538024&partnerID=MN8TOARS}, DOI={10.1007/s10853-010-5102-3}, number={8}, journal={Journal of Materials Science}, author={Jagannadham, K. and Lance, M.J. and Butler, J.E.}, year={2011}, pages={2518–2528} }
 @article{jagannadham_2011, title={Thermal conductivity of Indium-graphene and Indium-gallium-graphene composites}, volume={40}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-78650746645&partnerID=MN8TOARS}, DOI={10.1007/s11664-010-1391-1}, number={1}, journal={Journal of Electronic Materials}, author={Jagannadham, K.}, year={2011}, pages={25–34} }
 @article{jagannadham_2009, title={Diffusion at a planar interface using continuous distribution of sources}, volume={105}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-59349105895&partnerID=MN8TOARS}, DOI={10.1063/1.3065530}, abstractNote={Many investigations of films grown on planar substrates at higher temperatures are accompanied by interdiffusion of atomic species across the planar interface from the substrate into the film and from the film into the substrate. In the present work, a new analysis is presented so that the concentration profiles of the diffusing species with different diffusion coefficients are determined. The analysis is carried out using the mathematical method of continuous distribution of diffusing sources in the two phases. The two boundary conditions in the form of continuity of flux and concentration at the interface are used to solve for the two distribution functions. These results are used to solve for the concentration profiles resulting from the mass diffusion in the two-phase medium. Application of the solution to a bilayer system with a planar interface and different diffusion coefficients in the adjoining phases is provided to illustrate the use of this method to several situations.}, number={2}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={2009} }
 @article{jagannadham_watkins_lance_riester_lemaster_2009, title={Laser physical vapor deposition of boron carbide films to enhance cutting tool performance}, volume={203}, ISSN={["0257-8972"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-67349177306&partnerID=MN8TOARS}, DOI={10.1016/j.surfcoat.2009.03.049}, abstractNote={Abstract Laser physical vapor deposition was used to deposit thin films of boron carbide on Si (100) and WC–Co substrates at 550 °C under different pressures of methane atmosphere. Grazing incidence X-ray diffraction was used to identify a boron carbide phase, which exhibited weak peaks. The presence of particulates in the size range of 50 nm–3 µm embedded in an amorphous matrix was observed by scanning electron microscopy. Raman spectroscopy indicated that as methane partial pressure was increased during deposition, the amount of disorder with the boron carbide structure also increased. Also, the nanoindentation hardness decreased, while the coefficient of friction and scratch adhesion strength increased. These effects are attributed to an increase in amorphous phase/disorder in the films. Wear tests conducted by machining particleboard using boron carbide coated WC–Co tools in the absence of methane showed the same wear rate as tools coated under higher methane pressures.}, number={20-21}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Jagannadham, K. and Watkins, T. R. and Lance, M. J. and Riester, L. and Lemaster, R. L.}, year={2009}, month={Jul}, pages={3151–3156} }
 @article{jagannadham_howe_allard_2010, title={Laser physical vapor deposition of nanocrystalline dots using nanopore filters}, volume={98}, ISSN={["1432-0630"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-72149116429&partnerID=MN8TOARS}, DOI={10.1007/s00339-009-5432-7}, number={2}, journal={APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING}, author={Jagannadham, K. and Howe, J. and Allard, L. F.}, year={2010}, month={Feb}, pages={285–292} }
 @article{jagannadham_berkman_elmasry_2008, title={Thermal conductivity of semi-insulating, p-type, and n-type GaN films on sapphire}, volume={26}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-42949135532&partnerID=MN8TOARS}, DOI={10.1116/1.2899379}, abstractNote={The thermal conductivity of undoped, n-type, and p-type GaN films deposited on (0001) substrates of sapphire was measured by the 3-ω method in the temperature range between 215 and 300K. The thickness, thermal conductivity, and heat capacity of the individual layers were used to simulate the experimental value of the increment in temperature of the heater using a multilayer model. The thermal conductivity of undoped GaN film was found to be much higher than that of p-type film. Also, the thermal conductivity of n-type GaN film was slightly smaller than that of p-type film. Modeling of the temperature dependence of the thermal conductivity in the films showed that phonon-dopant and three-phonon umklapp scattering are important. Smaller thickness and hence smaller volume fraction of the film with lower dislocation density was also found to be responsible for lower thermal conductivity in n- and p-type GaN films.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Jagannadham, K. and Berkman, E. A. and Elmasry, N.}, year={2008}, month={May}, pages={375–379} }
 @article{jagannadham_2007, title={Compound semiconductor bonded to AlN heat spreader substrate using graded intermediate layer}, volume={25}, ISSN={0734-2101 1520-8559}, url={http://dx.doi.org/10.1116/1.2722762}, DOI={10.1116/1.2722762}, abstractNote={The present work illustrates a novel method of bonding compound semiconductor wafers to AlN or AlN/diamond heat spreaders using a graded intermediate layer. The procedure is illustrated using In–Ga solder to bond GaSb (111) wafer to commercial AlN substrate. Thermal conductivity of three bonded structures was evaluated using the 3-ω method. The experimental measurements of thermal conductivity of the multilayer were simulated using the analysis applicable to a layered structure. The results illustrate that the thin intermediate graded layer has a thermal conductivity above that of GaSb and therefore does not form an insulating layer. Bonding ZnO (002) wafer to commercial AlN substrate using zinc film that is subsequently oxidized is illustrated. The advantages of the graded intermediate layer to bond the heat spreaders such AlN or AlN/diamond are highlighted.}, number={3}, journal={Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films}, publisher={American Vacuum Society}, author={Jagannadham, K.}, year={2007}, month={May}, pages={536–542} }
 @article{jagannadham_watkins_lance_2006, title={Interfacial characterization and residual stress analysis in diamond films on LiNbO <inf>3</inf>}, volume={24}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33750958880&partnerID=MN8TOARS}, DOI={10.1116/1.2356479}, abstractNote={Diamond films were deposited via microwave plasma chemical vapor deposition on lithium niobate (LN) substrates. Characterization of the interfacial regions formed between diamond films and LN substrates was carried out by several techniques. Secondary ion mass spectroscopy (SIMS) was used to determine the depth profiles of carbon, lithium, niobium, and oxygen in the LN substrate covered with diamond nuclei and in the substrate without nucleation. Results indicate that the diamond nuclei promoted growth of diamond, and in addition, a reduced depth of the lithium deficient zone formed in the LN substrate was observed. Grazing incidence x-ray diffraction and transmission electron microscopy observations corroborated the results obtained by SIMS. Residual stresses determined experimentally by an x-ray method or by the shift in the characteristic diamond peak in Raman spectroscopy were much smaller than the calculated thermal residual stresses. The results further emphasize that the interfacial phases are responsible for relieving the thermal stresses generated during cooling of the layered structure. The thickness of the interfacial region was found to be well below for attenuation of the surface acoustic waves in the gigahertz frequency surface acoustic wave devices.}, number={6}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K. and Watkins, T.R. and Lance, M.J.}, year={2006}, pages={2105–2112} }
 @article{jagannadham_reed_lance_watkins_verghese_butler_smirnov_2007, title={Neutron transmutation of B-10 doped diamond}, volume={16}, ISSN={["1879-0062"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33751334357&partnerID=MN8TOARS}, DOI={10.1016/j.diamond.2006.03.019}, abstractNote={Free standing 10B isotope doped diamond films deposited by chemical vapor deposition in a microwave chamber were irradiated to thermal neutron fluence values of 0.32 × 1019, 0.65 × 1019, 1.3 × 1019, and 2.6 × 1019 n/cm2. Cooling of the diamond films was maintained during irradiation. In a separate experiment, neutron irradiation to a total fluence of 2.4 × 1020 n/cm2 with equal fast and thermal neutrons was also performed on a diamond epilayer without cooling during irradiation. The formation of defects in the diamond films was characterized using Raman, FTIR, photoluminescence, electron paramagnetic resonance spectroscopy, and X-ray diffraction. It was found that defect configurations in diamond responsible for an increase in continuum background in the one-phonon region of Raman spectrum were absent in the films that have been cooled. The FTIR peak at 1530 cm− 1 annealed in the sample irradiated to a fluence of 2.6 × 1019 n/cm2 indicating that the sample reached a temperature of 300 °C during irradiation. Absence of characteristic infrared absorption peaks that were observed only upon annealing neutron irradiated diamond is used to conclude that the temperature of the sample during neutron irradiation to a fluence of 2.6 × 1019 n/cm2 was well below 650 °C needed for mobility of defects and accumulation of stable unrecoverable damage. On the other hand, results from diamond epilayer subjected to equal thermal and fast neutron fluence of 2.4 × 1020 n/cm2 and without cooling showed that defects formed from displaced carbon atoms became mobile and formed complex configurations of irrecoverable damage. Electrical conductance of the unirradiated and irradiated diamond samples was measured as a function of temperature to determine the compensation of the p-type by the n-type charge carriers.}, number={1}, journal={DIAMOND AND RELATED MATERIALS}, author={Jagannadham, K. and Reed, M. L. and Lance, M. J. and Watkins, T. R. and Verghese, K. and Butler, J. E. and Smirnov, A.}, year={2007}, month={Jan}, pages={50–62} }
 @article{scheffing_jagannadham_yim_bourham_farmer_haslam_day_fix_yang_2006, title={Properties of titanium-nitride for high-level waste packaging enhancement}, volume={156}, ISSN={["0029-5450"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33751356018&partnerID=MN8TOARS}, DOI={10.13182/NT156-213}, abstractNote={A feasibility study of applying titanium-nitride (TiN) coating onto waste package surfaces was performed as part of efforts to enhance the long-term performance of high-level waste packages. The hypothesis examined in the study is that a successful TiN coating would provide an effective mass-transport barrier thus preventing corrosion. In the present work, single-layer TiN and multiple-layer TiN + Ti, TiN + Ti + TiN, and ZrO2 + TiN were deposited on Type 316L stainless steel substrates. The coated samples were tested for corrosion properties in different types of water using polarization and weight loss tests. Results of corrosion testing are presented and discussed.}, number={2}, journal={NUCLEAR TECHNOLOGY}, author={Scheffing, C. C. and Jagannadham, K. and Yim, M. -S. and Bourham, M. A. and Farmer, J. C. and Haslam, J. J. and Day, S. D. and Fix, D. V. and Yang, N. Y.}, year={2006}, month={Nov}, pages={213–221} }
 @article{jagannadham_2006, title={Thermal conductivity of AlN-diamond particulate composite films on silicon}, volume={24}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33745509258&partnerID=MN8TOARS}, DOI={10.1116/1.2198862}, abstractNote={The thermal conductivity of a particulate composite film of diamond in AlN deposited on silicon was measured using 3ω technique in the temperature range of 205–300K. The experimental results of increase in the temperature of heater line were analyzed using a model of film on semi-infinite substrate. The results of modeling are found to conform to the expected temperature dependence of the thermal conductivity of silicon, AlN, and diamond. Oxygen introduced during the deposition of the AlN-diamond composite film on silicon is found to reduce the thermal conductivity of the film and the substrate. Low cost AlN-diamond particulate composite films are found to offer good heat spreader characteristics for high power semiconductor devices.}, number={4}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K.}, year={2006}, pages={895–899} }
 @inproceedings{scheffing_yim_bourham_kasichainula_2005, title={Properties of titanium-nitride for high level waste packaging enhancement}, volume={93}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33244457450&partnerID=MN8TOARS}, booktitle={Transactions of the American Nuclear Society}, author={Scheffing, C.C. and Yim, M.-S. and Bourham, M. and Kasichainula, J.}, year={2005}, pages={709–710} }
 @article{reed_reed_jagannadham_verghese_bedair_el-masry_butler_2004, title={Electrical characterization of B-10 doped diamond irradiated with low thermal neutron fluence}, volume={22}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-4344661941&partnerID=MN8TOARS}, DOI={10.1116/1.1763910}, abstractNote={A sample of B10 isotope doped diamond was neutron irradiated to a thermal fluence of 1.3×1019 neutron cm−2. The diamond sample was cooled continuously during irradiation in a nuclear reactor. Li7 is formed by nuclear transmutation reaction from B10. Characterization for electrical conductance in the temperature range of 160 K<T<600 K was performed on an unirradiated B10 doped sample and the B10 doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T>200 K) and p-type surface conductance at lower temperature (T<200 K). The irradiated sample showed decreasing conductance below 230 K and increasing conductance above 230 K with increasing temperature. Furthermore, the conductance showed a decrease above 400 K followed by an increase above 500 K. The observed behavior below 400 K with increase in temperature is interpreted in terms of compensation of surface p-type carriers by n-type bulk carriers generated from Li7 that is formed by nuclear transmutation reaction from B10 atoms. Also, compensation of n-type carriers from Li7 by p-type carriers from B10 is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type Li7 are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from B10 doped diamond is a useful method to achieve n-type conductivity in diamond.}, number={4}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Reed, ML and Reed, MJ and Jagannadham, K and Verghese, K and Bedair, SM and El-Masry, N and Butler, JE}, year={2004}, pages={1191–1194} }
 @article{jagannadham_lance_watkins_2004, title={Growth of diamond film on single crystal lithium niobate for surface acoustic wave devices}, volume={22}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-4344645575&partnerID=MN8TOARS}, DOI={10.1116/1.1740770}, abstractNote={Single crystalline lithium niobate thin films on diamond are useful for surface acoustic wave devices that operate at gigahertz frequency. The differences in the atomic bonding and crystalline structure between the lithium niobate and diamond and the high interfacial energy were responsible for formation of microcrystalline films of lithium niobate deposited on polycrystalline diamond. We have carried out growth of continuous diamond layer on single crystal lithium niobate by microwave chemical vapor deposition to overcome the above deficiencies. The temperature of the substrate during deposition has been maintained near 700 °C to reduce the loss of lithium from lithium niobate and to reduce the thermal stresses. Characterization by x-ray diffraction and Raman spectroscopy showed that the lithium niobate lattice is preserved without incorporation of carbon and the diamond layer is free from graphitic carbon. The integrated lithium niobate-diamond layered structure is shown to be suitable for surface acoustic wave devices.}, number={4}, journal={Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}, author={Jagannadham, K. and Lance, M.J. and Watkins, T.R.}, year={2004}, pages={1105–1109} }
 @article{makala_jagannadham_sales_2003, title={Pulsed laser deposition of Bi2Te3-based thermoelectric thin films}, volume={94}, ISSN={["1089-7550"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0141990549&partnerID=MN8TOARS}, DOI={10.1063/1.1600524}, abstractNote={Thin films of p-type Bi0.5Sb1.5Te3, n-type Bi2Te2.7Se0.3, and n-type (Bi2Te3)90(Sb2Te3)5(Sb2Se3)5 (with 0.13 wt % SbI3) were deposited on substrates of mica and aluminum nitride (on silicon) using pulsed laser ablation at substrate temperatures between 300 °C to 500 °C. The films were characterized using x-ray diffraction and transmission electron microscopy for crystalline quality and epitaxial growth on the substrates. The surface morphology and microstructure were examined using scanning electron microscopy. X-ray mapping and energy-dispersive spectroscopy were performed to determine nonstoichiometry in the composition and homogeneity. The quality of the films, in terms of stoichiometric composition and crystal perfection, was studied as a function of growth temperature and laser fluence. The values of the Seebeck coefficient, electrical resistivity, and Hall mobility in the thin films were measured and compared with those in the bulk. Thermoelectric figure of merit of the films was evaluated from the measured parameters. Correlation of the thermoelectric properties, with the crystalline quality and stoichiometric composition of the films, showed the advantages of pulsed laser deposition of the multicomponent thermoelectric thin films. The results illustrate that laser physical vapor deposition is a suitable choice for deposition of multicomponent thermoelectric films. However, optimization of target composition, substrate temperature, and annealing of the films after deposition were found necessary to maintain the desired stoichiometry and low defect density. AlN/Si substrates provided better quality films compared to substrates of mica. Poor adhesion and cracking of the films on mica were found to be detrimental factors. Films deposited on AlN/Si substrates were found to show higher carrier mobility and higher values of Seebeck coefficient.}, number={6}, journal={JOURNAL OF APPLIED PHYSICS}, author={Makala, RS and Jagannadham, K and Sales, BC}, year={2003}, month={Sep}, pages={3907–3918} }
 @inproceedings{makala_yoganand_jagannadham_lemaster_bailey_2002, title={Diamond coated WC tools for machining wood and particle board}, volume={697}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036450231&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Makala, R.S. and Yoganand, S.N. and Jagannadham, K. and Lemaster, R.L. and Bailey, J.}, year={2002}, pages={347–352} }
 @article{raghuveer_yoganand_jagannadham_lemaster_bailey_2002, title={Improved CVD diamond coatings on WC-Co tool substrates}, volume={253}, ISSN={["0043-1648"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036951335&partnerID=MN8TOARS}, DOI={10.1016/S0043-1648(02)00244-2}, abstractNote={Tungsten carbide tools with different cobalt concentrations (3 and 6%) have been treated with different surface cleaning procedures for deposition of diamond and multilayer diamond composite films. Cleaning with organic solvents, surface etching to remove cobalt from the surface, and hydrogen plasma etching to decarburize WC and etch remove cobalt have been used in combination to improve the adhesion of diamond films deposited on the tool substrates. Diamond layers are deposited by microwave plasma chemical vapor deposition (MPCVD) after introducing surface nucleation by suspension with sub-micron size diamond crystallites. TiN and TiC films are deposited as intermediate layers that prevent diffusion of cobalt or as embedding layers that also anchor diamond crystallites to the tool substrate. A continuous top layer of diamond was deposited for different periods of time (15–36 h) to obtain diamond film thickness ranging from 15 to 36 μm. The performance of diamond-coated tools has been tested by machining particleboard. The tool surfaces were characterized using measurements of wear of the cutting edge. Microstructural characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the composite layers on the tool surfaces is performed. The quantitative evaluation of wear and microstructural characterization were used to determine the mechanisms of wear of the cutting edge. The results are used to conclude the diamond tool coating procedure that provides the best performance in machining particleboard.}, number={11-12}, journal={WEAR}, author={Raghuveer, MS and Yoganand, SN and Jagannadham, K and Lemaster, RL and Bailey, J}, year={2002}, month={Dec}, pages={1194–1206} }
 @article{yoganand_jagannadham_karoui_wang_2002, title={Integrated AlN/diamond heat spreaders for silicon device processing}, volume={20}, ISSN={["0734-2101"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036863138&partnerID=MN8TOARS}, DOI={10.1116/1.1513643}, abstractNote={Growth and characterization of AlN and diamond films on the backside of a Si (100) wafer and the integration of AlN/diamond heat spreaders into silicon device technology is investigated. AlN film was deposited by pulsed dc reactive magnetron sputtering at 600 °C and diamond film was deposited by microwave plasma chemical vapor deposition at 900 °C. The films were characterized by x-ray diffraction and transmission electron microscopy for crystalline quality, by scanning electron microscopy for morphology, and by infrared thermography for heat spreading characteristics. The heat spreading characteristics of the silicon wafer with the composite AlN/diamond films were found to be superior to that of wafers with no heat spreaders or to the wafers with either single layer diamond or single layer AlN heat spreaders. Deep level transient spectroscopy and secondary ion mass spectroscopy were performed on the samples with and without the heat spreader to determine the concentration of the impurities that may have been introduced during deposition of AlN or diamond. The results showed that the purity of the wafers is not altered due to the deposition of AlN and diamond and subsequent device processing steps such as high temperature oxidation. The device characteristics were studied by fabrication of Schottky diodes on the wafers with the composite AlN/diamond heat spreader and compared with that of devices on wafers with no heat spreader. The device characteristics were found to be similar and unaffected by integration with an AlN/diamond heat spreader. Integration of AlN/diamond heat spreaders with silicon device processing has been shown to be successful.}, number={6}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS}, author={Yoganand, SN and Jagannadham, K and Karoui, A and Wang, H}, year={2002}, pages={1974–1982} }
 @article{makala_jagannadham_sales_wang_2002, title={Microstructure and thermoelectric properties of p-type Bi<inf>0.5</inf>Sb<inf>1.5</inf>Te<inf>3</inf> and n-type Bi<inf>2</inf>Te<inf>2.7</inf>Se<inf>0.3</inf> films deposited by pulsed laser ablation}, volume={691}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036352116&partnerID=MN8TOARS}, journal={Materials Research Society Symposium - Proceedings}, author={Makala, R.S. and Jagannadham, K. and Sales, B.C. and Wang, H.}, year={2002}, pages={189–194} }
 @article{yoganand_raghuveer_jagannadham_wu_karoui_rozgonyi_2002, title={Multilayer TiC/TiN diffusion barrier films for copper}, volume={80}, ISSN={["1077-3118"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-79955988332&partnerID=MN8TOARS}, DOI={10.1063/1.1430027}, abstractNote={TiC/TiN thin films deposited by reactive magnetron sputtering on Si (100) substrates were investigated by transmission electron microscopy for microstructure and by deep level transient spectroscopy (DLTS) for diffusion barrier against copper. TiN thin films deposited on Si substrates at a substrate temperature of 600 °C were textured, and TiC thin films deposited at the same temperature were polycrystalline. TiC/TiN multilayer films also showed the same characteristics with the formation of an additional interaction layer. The diffusion barrier characteristics of the TiC/TiN/Si were determined by DLTS and the results showed that the films completely prevented diffusion of copper into Si.}, number={1}, journal={APPLIED PHYSICS LETTERS}, author={Yoganand, SN and Raghuveer, MS and Jagannadham, K and Wu, L and Karoui, A and Rozgonyi, G}, year={2002}, month={Jan}, pages={79–81} }
 @article{jagannadham_watkins_dinwiddie_2002, title={Novel heat spreader coatings for high power electronic devices}, volume={37}, ISSN={["0022-2461"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036531178&partnerID=MN8TOARS}, DOI={10.1023/A:1014568512077}, number={7}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Jagannadham, K and Watkins, TR and Dinwiddie, RB}, year={2002}, month={Apr}, pages={1363–1376} }
 @article{jagannadham_wang_2002, title={Thermal resistance of interfaces in AlN-diamond thin film composites}, volume={91}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0036469393&partnerID=MN8TOARS}, DOI={10.1063/1.1428103}, abstractNote={The effective thermal conductivity of single and multilayer AlN/diamond composite films deposited on silicon substrate with a planar interface is determined experimentally. As a result of the small thickness and the good crystalline quality of the AlN and diamond films, the contribution to the effective thermal resistivity from the films remained very small and enabled the evaluation of the thermal barrier resistance associated with the interfaces. The interfacial thermal resistance of AlN/Si, diamond/Si, and AlN/diamond interfaces was evaluated from the experimental measurements of the effective thermal conductivity of the layered structures. The results show that amorphous regions formed along the interfaces are responsible for high thermal resistance in the layered structures. Modeling of the interfacial thermal resistance has been carried out to explain the effective thermal conductivity of the single and multilayer AlN/diamond composite films in terms of the microstructure of the interfaces.}, number={3}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Wang, H.}, year={2002}, pages={1224–1235} }
 @article{jagannadham_verghese_butler_2001, title={Neutron transmutation of B-10 isotope-doped diamond}, volume={78}, ISSN={["0003-6951"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0042331197&partnerID=MN8TOARS}, DOI={10.1063/1.1342207}, abstractNote={Diamond samples grown by microwave plasma chemical vapor deposition and doped with 10B have been irradiated under thermal neutron flux of 1013 cm−2 s−1 for 76 h to examine transmutation of 10B to 7Li and the attendant lattice damage to diamond. To prevent graphitization and formation of diamond-like carbon, continuous cooling in water is provided during irradiation. Characterization of the diamond samples using Raman spectroscopy, photoluminescence spectroscopy, and secondary ion mass spectrometry showed that diamond remained crystalline without a major damage. Formation of vacancies due to neutron irradiation is inferred from photoluminescence spectroscopy.}, number={4}, journal={APPLIED PHYSICS LETTERS}, author={Jagannadham, K and Verghese, K and Butler, JE}, year={2001}, month={Jan}, pages={446–447} }
 @article{sharma_narayan_narayan_jagannadham_2000, title={Structural and tribological characteristics of diamond-like carbon films deposited by pulsed laser ablation}, volume={77}, ISSN={["0921-5107"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0034250566&partnerID=MN8TOARS}, DOI={10.1016/S0921-5107(00)00434-7}, abstractNote={Diamond-like carbon (DLC) films were deposited by pulsed laser ablation (PLA) on Si (100) and Ti–6Al–4V alloy substrates at four different temperatures. The bonding characteristics of the films were studied by X-ray photoelectron (XPS) and Raman spectroscopy techniques. The ratio of tetrahedral to trigonally coordinated carbon atoms was estimated by XPS successfully. The fraction of tetrahedrally bonded atoms in the films deposited on Si at room temperature was estimated to be ∼63 at.% which decreased to ∼33 at.% as the substrate temperature increased to 400°C. The Raman spectroscopy results of these specimens agree qualitatively with these observations. Also, using Raman spectroscopy, the residual compressive stress was also estimated in fully adherent films on Si substrate to be ∼3 GPa with reference to the value of stress present in a free-standing peeled off film from the Ti-alloy substrate. This value is consistent with the residual stresses estimated in the earlier results. The abrasive wear rates have been correlated during the initial stages of the well adhered films with the sp3/sp2 ratios. The importance of suitable dopants and the interfacial interlayers in reducing internal compressive stresses in these films is discussed.}, number={2}, journal={MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY}, author={Sharma, AK and Narayan, RJ and Narayan, J and Jagannadham, K}, year={2000}, month={Aug}, pages={139–143} }
 @article{oktyabrsky_kalyanaraman_jagannadham_narayan_1999, title={Dislocation structure of low-angle grain boundaries in YBa2Cu3O7-delta/MgO films}, volume={14}, ISSN={["0884-2914"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032678410&partnerID=MN8TOARS}, DOI={10.1557/JMR.1999.0369}, abstractNote={Grain boundaries in laser-deposited YBa2Cu3O7−δ(YBCO)/MgO thin films have been investigated by high-resolution transmission electron microscopy. The films exhibit perfect texturing with YBCO(001)/MgO(001) giving rise to low-angle [001] tilt grain boundaries resulting from the grains with thecaxis normal to the substrate surface and with misorientation in thea-bplane. The atomic structure of the grain boundaries was analyzed by using a dislocation model. Low-angle grain boundaries have been found to be aligned along (100) and (110) interface planes. For the (110) boundary plane, the low-energy dislocation configuration was found to consist of an array of alternating [100] and [010] dislocations. We have calculated the energy of various configurations and shown that the energy of the (110) boundary with dissociated dislocations is comparable to that of the (100) boundary, which explains the coexistence of (100) and (110) interface facets along the boundary. We have also modeled critical current transport through grain boundaries with various structures and found that the low-energy (110) grain boundary with dissociated dislocation array is expected to transport a lower superconducting current (by 25% for 6° misorientation) than (100) boundaries.}, number={7}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Oktyabrsky, S and Kalyanaraman, R and Jagannadham, K and Narayan, J}, year={1999}, month={Jul}, pages={2764–2772} }
 @article{jagannadham_1999, title={Model of interfacial thermal resistance of diamond composites}, volume={17}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0033465465&partnerID=MN8TOARS}, DOI={10.1116/1.581597}, abstractNote={The effective thermal conductivity of diamond and aluminum nitride layered composites was analyzed for three different types of interfaces. A sharp interface with a stepwise discontinuity, a graded interface with a linear variation and a diffused interface with a minimum or a maximum in thermal conductivity across the interface were considered. The results of the modeling analysis were used to explain the experimental results described in the literature of improved heat spreader characteristics of diamond and aluminum nitride composites.}, number={2}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Jagannadham, K}, year={1999}, pages={373–379} }
 @article{mallika_ramamohan_jagannadham_komanduri_1999, title={On the growth of polycrystalline diamond on transition metals by microwave-plasma-assisted chemical vapour deposition}, volume={79}, ISSN={["0141-8637"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032664013&partnerID=MN8TOARS}, DOI={10.1080/13642819908205738}, abstractNote={Abstract The role of transition-metal substrates on the deposition of polycrystalline diamond was investigated using a microwave—plasma-assisted chemical vapour deposition process. Diamond deposition was carried out on the transition elements of the first series (3d block) and on the elements belonging to groups VB and VIB. It was found that the chemical nature of the transition metals plays an important role in the formation of diamond. Similarity in morphological features was observed on the diamond films grown on the substrates belonging to the same group. Micro-Raman (μ-Raman) spectroscopy indicated that diamond films on substrates belonging to groups VB and VIB have lower internal stresses than those deposited on group VIII. An attempt was made to relate the trends observed from the μ-Raman spectroscopy to the chemical properties of the transition elements. The mechanism of diamond growth seem to vary across the period. Elements belonging to the first half of the transition series, namely Ti, V. Nb, ...}, number={4}, journal={PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES}, author={Mallika, K and Ramamohan, TR and Jagannadham, K and Komanduri, R}, year={1999}, month={Apr}, pages={593–624} }
 @inproceedings{kalyanaraman_oktyabrsky_jagannadham_narayan_1998, title={Atomic structure and property correlation in pulsed laser deposited high-Tc films}, volume={526}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032316887&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Kalyanaraman, R. and Oktyabrsky, S. and Jagannadham, K. and Narayan, J.}, year={1998}, pages={281–286} }
 @inproceedings{jagannadham_watkins_1998, title={Comparative study of residual stresses in single and multilayer composite diamond coatings}, volume={505}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031621445&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Jagannadham, K. and Watkins, T.R.}, year={1998}, pages={391–396} }
 @inproceedings{jagannadham_sharma_wei_kalyanraman_narayan_1998, title={Comparison of AlN films synthesized by pulsed laser ablation and magnetron sputtering techniques}, volume={505}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031629667&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Jagannadham, K. and Sharma, A.K. and Wei, Q. and Kalyanraman, R. and Narayan, J.}, year={1998}, pages={469–474} }
 @article{jagannadham_wilsdorf_weertman_1998, title={Dislocations at ductile/plastic crack tips: in-situ TEM observations}, volume={1}, ISSN={["1432-8917"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-24044483938&partnerID=MN8TOARS}, DOI={10.1007/s100190050050}, abstractNote={In-situ observations of dislocation structures ahead of crack tips in TEM metal foils are reviewed. Two cases are compared in particular: Structure development during in-situ straining to failure of (i) electron-transparent foils ahead of the tip of a growing crack that spreads from the thinnest regions or perforations and (ii) initially non-transparent thick foils. In the latter case cracks formed only after substantial in-situ straining, and they propagated along dislocation cell walls via repeated stimulated crack nucleation ahead of the tip. This behavior was shown to adequately simulate bulk behavior and such cracks do not exhibit dislocation-free zones at their tips. By contrast, dislocation-free regions along ligaments formed by crack propagation and observed in thin (e.g. about 100 nm or less) TEM foils are found to be artifacts due to strong dislocation image forces. These image forces at the same time limit mutual dislocation interactions to the thickness of the foil, and rotate the dislocations to be normal to the foil plane, meanwhile straightening them. This behavior has no correspondence to conditions at real cracks in bulk materials. Theoretical expressions are derived for the dislocation densities ahead of crack tips that give rise to long-range and shorter range stress fields in mode I crack tip configurations, respectively.}, number={4}, journal={MATERIALS RESEARCH INNOVATIONS}, author={Jagannadham, K and Wilsdorf, HGF and Weertman, J}, year={1998}, month={Feb}, pages={254–264} }
 @article{jagannadham_1998, title={Multilayer diamond heat spreaders for electronic power devices}, volume={42}, ISSN={["0038-1101"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032304412&partnerID=MN8TOARS}, DOI={10.1016/S0038-1101(98)00216-0}, abstractNote={Single layer diamond and multilayer diamond heat spreader substrates are prepared and bonded to device wafers of silicon and gallium arsenide. Metallization schemes for the diamond surface and the backside of the device wafers are described. Bonding of the device wafers to the diamond substrates using the high thermal conductivity gold–tin eutectic solder is carried out. Characterization of the bond for the distribution of different elements in the metallization layers and the solder, for the presence of microscopic defects such as voids and cracks, for the adhesion strength and for the stability of the bond under thermal cycling is performed. The heat spreader characteristics of the substrates with single and multlayer diamond are determined using infrared imaging of the bonded device wafers and compared with that of wafers bonded to metal substrates. Modeling and analysis of the effectivethermal conductivity showed that the multilayer diamond substrates are better heat spreaders and reduce the device temperature so that the life of the electronic devices is prolonged.}, number={12}, journal={SOLID-STATE ELECTRONICS}, author={Jagannadham, K}, year={1998}, month={Dec}, pages={2199–2208} }
 @article{jagannadham_sharma_wei_kalyanraman_narayan_1998, title={Structural characteristics of AIN films deposited by pulsed laser deposition and reactive magnetron sputtering: A comparative study}, volume={16}, ISSN={["0734-2101"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0032370406&partnerID=MN8TOARS}, DOI={10.1116/1.581425}, abstractNote={Aluminum nitride films have been deposited on Si(111) substrates at different substrate temperatures using two techniques; pulsed laser deposition or reactive magnetron sputtering. The films deposited by either of the techniques have been characterized by x-ray diffraction and transmission electron microscopy to determine the crystalline quality, grain size, and epitaxial growth relation with respect to the substrate. The bonding characteristics and the residual stresses present in the films have been evaluated using Raman and Fourier transform infrared spectroscopy. Secondary ion mass spectrometry has been performed to determine the nitrogen stoichiometry and the presence of impurities such as oxygen and silicon. The adhesion strength of the AlN films to the silicon substrate and the wear resistance have been determined by scratch test and a specially designed microscopic wear test. A comparison of the different characteristic features associated with the AlN films deposited by pulsed laser deposition or magnetron sputtering is presented with particular emphasis to electronic and tribological applications.}, number={5}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS}, author={Jagannadham, K and Sharma, AK and Wei, Q and Kalyanraman, R and Narayan, J}, year={1998}, pages={2804–2815} }
 @inproceedings{narayan_wei_sharma_jagannadham_narayan_1998, title={Superhard biocompatible coatings}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031710366&partnerID=MN8TOARS}, booktitle={TMS Annual Meeting}, author={Narayan, R.J. and Wei, Q. and Sharma, A.K. and Jagannadham, K. and Narayan, J.}, year={1998}, pages={301–308} }
 @article{fan_jagannadham_narayan_1997, title={Adhesion of diamond films on Ti-6Al-4V alloys}, volume={91}, ISSN={["0257-8972"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031131508&partnerID=MN8TOARS}, DOI={10.1016/S0257-8972(96)03107-6}, abstractNote={Diamond films have been successfully grown on Ti (Al 6%, V 4%) alloy by hot filament chemical vapor deposition (HFCVD). Different gas mixtures of methane to hydrogen and substrate temperatures were used in order to deposit high quality diamond films. Scanning electron microscopy (SEM), X-ray diffraction, Raman spectroscopy, and microhardness measurements have been used to characterize the diamond films. The results indicate that uniform high quality diamond films can be grown on the titanium alloy at a partial pressure of 2660 Pa, ratio of methane to hydrogen of 0.5-1%, filament temperature 2273 K, and substrate temperature 1073 K. The hardness of the Ti alloy is increased 30% by coating with the diamond film. The adhesion measurements indicate that diamond films grown on the Ti alloy have excellent adhesion.}, number={1-2}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Fan, WD and Jagannadham, K and Narayan, J}, year={1997}, month={May}, pages={32–36} }
 @article{jagannadham_fan_komanduri_narayan_1997, title={Comparison of microstructural features of diamond composite coatings with polycrystalline diamond or boron nitride brazed on tungsten carbide tools}, volume={15}, ISSN={["1520-8559"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031504189&partnerID=MN8TOARS}, DOI={10.1116/1.580733}, abstractNote={We have investigated microstructure and properties of diamond composite coatings on cemented tungsten carbide tool substrates, and compared wear resistance of these coatings with that of polycrystalline diamond (PCD) and polycrystalline boron nitride (PCBN) tools brazed on to cemented tungsten carbide substrates. The diamond composite coatings consist of layers of discontinuous diamond, TiC, and continuous diamond. In these composite layers, diamond is deposited by hot filament chemical vapor deposition and TiC by pulsed laser physical vapor deposition. Thermal stresses in the composite layer and the substrate are reduced and thereby help to improve the adhesion of diamond to the tool substrate. These tool coatings are characterized by scanning electron microscopy, Raman spectroscopy, secondary ion mass spectroscopy, and x-ray diffraction. The results of microstructural characterization and analysis of chemical composition are correlated with wear resistance. The present results demonstrate the advantages associated with composite diamond coatings compared to PCD and PCBN tool coatings.}, number={4}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Jagannadham, K and Fan, ND and Komanduri, R and Narayan, J}, year={1997}, pages={2262–2275} }
 @inproceedings{ramaswami_jagannadham_1997, title={Heat spreader characteristics of multilayer diamond films for high frequency power devices}, volume={483}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031380152&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Ramaswami, B. and Jagannadham, K.}, year={1997}, pages={69–74} }
 @article{kalyanaraman_vispute_oktyabrsky_dovidenko_jagannadham_narayan_budai_parikh_suvkhanov_1997, title={Influence of oxygen background pressure on crystalline quality of SrTiO3 films grown on MgO by pulsed laser deposition}, volume={71}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.120011}, DOI={10.1063/1.120011}, abstractNote={We have systematically investigated the effect of oxygen partial pressure (PO2) on the crystalline quality of SrTiO3 films grown on MgO (001) substrates using pulsed laser deposition and established optimized conditions for the growth of high-quality epitaxial films. The crystalline quality is found to improve significantly in the O2 pressure range of 0.5–1 mTorr, compared to the films deposited at higher pressures of 10–100 mTorr. The x-ray diffraction rocking curves for the films grown at PO2 of 1 mTorr and 100 mTorr yielded full width at half-maximum (FWHM) of 0.7° and 1.4°, respectively. The in-plane x-ray φ scans showed epitaxial cube-on-cube alignment of the films. Channeling yields χmin were found to be <5% for the 1 mTorr films and ∼14% for 100 mTorr films. Thermal annealing of the SrTiO3 films in oxygen further improves the quality, and the 1 mTorr films give FWHM of 0.13° and χmin of 1.7%. In-plane misorientations of the annealed SrTiO3 films calculated using results of transmission electron microscopy are ±0.7° for 1 mTorr and ±1.7° for the 10 mTorr film. The high temperature superconducting (high-Tc) Y1Ba2Cu3O7−δ films grown on these SrTiO3/MgO substrates showed a χmin of 2.0% and transition temperature of ∼92 K, indicating that SrTiO3 buffer layers on MgO can be used for growth of high-quality Y1Ba2Cu3O7−δ thin film heterostructures for use in high-Tc devices and next generation microelectronics devices requiring films with high dielectric constants.}, number={12}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Kalyanaraman, R. and Vispute, R. D. and Oktyabrsky, S. and Dovidenko, K. and Jagannadham, K. and Narayan, J. and Budai, J. D. and Parikh, N. and Suvkhanov, A.}, year={1997}, month={Sep}, pages={1709–1711} }
 @inproceedings{jagannadham_fan_dinwidde_narayan_1997, title={Multilayer composite diamond heat spreaders for electronic packaging}, volume={445}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0031341440&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Jagannadham, K. and Fan, W.D. and Dinwidde, R.B. and Narayan, J.}, year={1997}, pages={51–56} }
 @inproceedings{jagannadham_watkins_narayan_1997, title={Residual stresses in single and multilayer composite diamond coatings}, volume={458}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030702666&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Jagannadham, K. and Watkins, T.R. and Narayan, J.}, year={1997}, pages={459–464} }
 @article{weihnacht_fan_jagannadham_narayan_liu_1996, title={A new design of tungsten carbide tools with diamond coatings}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030243331&partnerID=MN8TOARS}, DOI={10.1557/JMR.1996.0282}, abstractNote={We have designed tungsten carbide tools with a new binder, which makes them suitable for advanced diamond tool coatings. The new tool substrates, made of tungsten carbide and nickel aluminide as binder phase, are produced by sintering and hot isostatic pressing, and also by combustion synthesis. The high temperature strength of nickel aluminide is key to superior tool performance at elevated temperatures. More importantly, nickel aluminides reduce the formation of graphite and promote diamond growth during chemical vapor deposition. Diamond films are deposited on the new tool substrates to investigate the nucleation density, adhesion, and wear resistance. The diamond coatings are characterized by scanning electron microscopy and Raman spectroscopy. The graphitizing tendency due to cobalt in the tungsten carbide tools was found to be a limitation to improve adhesion of diamond films. The new tool substrates with nickel aluminide binder have been found to exhibit good adhesion and wear resistance. The implications of these results in advanced cutting tools are discussed.}, number={9}, journal={Journal of Materials Research}, author={Weihnacht, V. and Fan, W.D. and Jagannadham, K. and Narayan, J. and Liu, C.-T.}, year={1996}, pages={2220–2230} }
 @inproceedings{fan_jagannadham_narayan_1996, title={Bonding silicon devices on diamond heat spreaders}, volume={416}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029736766&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Fan, W.D. and Jagannadham, K. and Narayan, J.}, year={1996}, pages={211–216} }
 @article{chowdhury_vispute_jagannadham_narayan_1996, title={Characteristics of titanium nitride films grown by pulsed laser deposition}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030172430&partnerID=MN8TOARS}, DOI={10.1557/JMR.1996.0182}, abstractNote={Laser physical vapor deposition (LPVD) has been used to grow titanium nitride films on hydrogen-terminated silicon(100) substrates at deposition temperatures ranging from room temperature to 600 °C. A pulsed KrF excimer laser (λ = 248 nm, τ = 25 ns) was used with the deposition chamber maintained at a base pressure of 10−7 Torr prior to deposition. Different properties of the films were investigated by x-ray diffraction, Auger electron spectroscopy, Raman spectroscopy, optical, scanning, and high resolution transmission electron microscopy, and measurement of electrical resistivity. When the substrate temperature was low (at and below 500 °C), oxygen atoms from the residual gases were incorporated in the films. The microstructures and resistivities of TiN films were found to be strongly dependent on the temperature of the silicon substrates. The TiN films deposited at 600 °C were oxygen-free, as observed from Auger analysis, and the room temperature resistivity was found to be 14–15 μΩ-cm. Raman spectroscopy of the films showed that the nitrogen-related optical phonon peak increased with deposition temperature in comparison with the titanium-related acoustic peak. Transmission electron microscopy and x-ray diffraction analyses showed that the films were polycrystalline at low temperature with grain size ranging from 300–600 Å, depending on the temperature of the substrate. At 600 °C, the films were found to be single crystals with occasional presence of dislocation loops. The spacing of Moiré fringes in TiN/Si samples deposited at 600 °C established the nearly periodic elastic strain field extending into the TiN and Si at the interface. Although there exists a large misfit between TiN and Si (24.6%), the epitaxial growth of TiN films on Si(100) substrates was explained by means of domain-matched epitaxy with a 4-to-3 match in unit cells for TiN/Si structure, giving rise to a residual lattice misfit of only 4%.}, number={6}, journal={Journal of Materials Research}, author={Chowdhury, R. and Vispute, R.D. and Jagannadham, K. and Narayan, J.}, year={1996}, pages={1458–1469} }
 @article{zheleva_oktyabrsky_jagannadham_vispute_narayan_1996, title={Characterization of highly oriented (110) TiN films grown on epitaxial Ge/Si(001) heterostructures}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030081370&partnerID=MN8TOARS}, DOI={10.1557/JMR.1996.0049}, abstractNote={The characteristics of epitaxial growth of titanium nitride films on Ge/Si(001) have been studied. The growth of titanium nitride and germanium films on (001)Si was carried out in situ in a high vacuum chamber (<10−7 Torr) using a multitarget stage in a pulsed laser deposition system. Electrical resistivity, stoichiometry, crystallinity, and epitaxial relationships as a function of deposition temperature have been studied. Electrical resistivity of the titanium nitride films grown at deposition temperatures in the range of 450 °C–750 °C was measured using a four-point probe. The stoichiometry of these films was investigated using Auger electron spectroscopy and Raman spectroscopy. The crystalline quality and epitaxial nature of TiN films grown at different substrate temperatures were characterized using x-ray diffraction and transmission electron microscopy. Highly oriented titanium nitride films with (110) orientation were obtained on Ge(001) film when the substrate temperature was maintained between 550 °C and 650 °C. The epitaxial growth of the titanium nitride films was found to be a function of two-dimensional or three-dimensional growth mode of germanium film on silicon (001) substrate. Titanium nitride films grown at a substrate temperature of 650 °C exhibited the lowest room temperature resistivity (26 μΩ-cm), highest nitrogen content (close to stoichiometry), and the best epitaxiality with the Ge(001) films on Si(001). The epitaxial relationships for the TiN/Ge/Si(001) heterostructure are found to be [001]TiN‖ [110]Ge‖ [110]Si and [110]TiN‖ [110] Ge‖ [110]Si. To explain the epitaxial growth in a large mismatch system (∼28%) such as TiN/Ge(001), the domain matching mechanism is proposed. Domains of size four (001)TiN by seventeen (220)TiN in the titanium nitride film match closely with domains of size three (220)Ge by sixteen (220)Ge in the germanium film, respectively. The lattice matching epitaxy involving a 4% mismatch between Ge and Si provides a mechanism for epitaxial growth of Ge on Si(001).}, number={2}, journal={Journal of Materials Research}, author={Zheleva, T. and Oktyabrsky, S. and Jagannadham, K. and Vispute, R.D. and Narayan, J.}, year={1996}, pages={399–411} }
 @article{narayan_nelson_oktyabrsky_jagannadham_1996, title={Diamond deposition on 3d transition metals and their alloys}, volume={38}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0037543552&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(95)01316-4}, abstractNote={The characteristics of formation of diamond films using hot-filament chemical vapor deposition on nickel and nickel-aluminum alloys have been investigated systematically. It has been found that the chemical nature of the substrate plays an important role in stabilization of graphite (sp2-bonded) or diamond (sp3-bonded) phase. The transition metal substrates with a partially filled 3d shell, for example nickel, tend to stabilize sp2 bonding and catalyze the formation of graphite. By alloying the substrate with aluminum, it was possible to form diamond directly on the NiAl substrates. The mechanism of formation of diamond on nickel-aluminum alloys, and the nucleation of diamond on single crystal graphite substrates are discussed. The importance of diamond coating on these technologically important structural alloys is described briefly.}, number={1-2}, journal={Materials Science and Engineering B}, author={Narayan, J. and Nelson, M. and Oktyabrsky, S. and Jagannadham, K.}, year={1996}, pages={46–52} }
 @inproceedings{vispute_dovidenko_jagannadham_narayan_1996, title={Epitaxial TiN films on sapphire and silicon-on-sapphire by pulsed laser deposition}, volume={397}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029745851&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Vispute, R.D. and Dovidenko, K. and Jagannadham, K. and Narayan, J.}, year={1996}, pages={271–276} }
 @inproceedings{vispute_wu_jagannadham_narayan_1996, title={Epitaxial growth of AlN thin films on silicon and sapphire by pulsed laser deposition}, volume={395}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029748160&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Vispute, R.D. and Wu, H. and Jagannadham, K. and Narayan, J.}, year={1996}, pages={325–330} }
 @inproceedings{jagannadham_narayan_hirth_1996, title={Equilibrium configuration of epitaxially strained thin film surfaces}, volume={399}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029702095&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Jagannadham, K. and Narayan, J. and Hirth, J.P.}, year={1996}, pages={383–388} }
 @article{vispute_narayan_dovidenko_jagannadham_parikh_suvkhanov_budai_1996, title={Heteroepitaxial structures of SrTiO<inf>3</inf>/TiN on Si(100) by in situ pulsed laser deposition}, volume={80}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0001288358&partnerID=MN8TOARS}, DOI={10.1063/1.363798}, abstractNote={High-quality ceramics based heteroepitaxial structures of oxide-nitride-semiconductors, i.e., SrTiO3/TiN/Si(100) have been fabricated by in situ pulsed laser deposition. The dependence of substrate temperature and oxygen partial pressure on the crystalline quality of the SrTiO3 films on Si with epitaxial TiN template has been examined. We found that epitaxial growth occurs on TiN/Si(100) above 500 °C, initially at a reduced O2 pressure (10−6 Torr), and followed by a deposition in the range of 5–10×10−4 Torr. X-ray diffraction (Θ, ω, and Φ scans) and transmission electron microscope (TEM) results revealed an excellent alignment of SrTiO3 and TiN films on Si(100) with a cube-on-cube epitaxy. Rutherford backscattering and ion channeling results show a channeling minimum yield (χmin) of ∼13% for the SrTiO3 films. High-resolution TEM results on the SrTiO3/TiN interface show that the epitaxial SrTiO3 film is separated from the TiN by an uniform 80–90 Å crystalline interposing layer presumably of TiNxO1−x (oxy-nitride). The SrTiO3 film fabricated at 700 °C showed a high relative dielectric constant of 312 at the frequency of 1 MHz. The electrical resistivity and the breakdown field of the SrTiO3 films were more than 5×1012 Ω cm and 6×105 V cm−1, respectively. An estimated leakage current density measured at an electric field of 5×105 V/cm−1 was less than 10−7 A/cm2.}, number={12}, journal={Journal of Applied Physics}, author={Vispute, R.D. and Narayan, J. and Dovidenko, K. and Jagannadham, K. and Parikh, N. and Suvkhanov, A. and Budai, J.D.}, year={1996}, pages={6720–6724} }
 @article{kumar_vispute_aboelfotoh_oktyabrsky_jagannadham_narayan_apte_pinto_1996, title={LaNiO<inf>3</inf> and Cu<inf>3</inf>Ge contacts to YBa<inf>2</inf>Cu<inf>3</inf>O<inf>7-x</inf> films}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0347988833&partnerID=MN8TOARS}, DOI={10.1007/s11664-996-0032-1}, number={11}, journal={Journal of Electronic Materials}, author={Kumar, D. and Vispute, R.D. and Aboelfotoh, O. and Oktyabrsky, S. and Jagannadham, K. and Narayan, J. and Apte, P.R. and Pinto, R.}, year={1996}, pages={1760–1766} }
 @article{fan_jagannadham_goral_1996, title={Multilayer diamond coatings on silicon carbide}, volume={81}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0030158048&partnerID=MN8TOARS}, DOI={10.1016/0257-8972(95)02476-X}, abstractNote={Abstract Multilayer composite diamond coatings on SiC substrates with improved adhesion and wear resistance have been developed. The coatings consist of a first layer of discontinuous diamond crystallites which are anchored to the SiC substrates by an interposing layer of TiC or TiN films. A top layer of continuous diamond film is grown epitaxially on the first layer. The diamond films and TiC or TiN films were deposited using hot filament chemical vapor depostion and laser physical vapor deposition, respectively. The diamond films were characterized by scanning electron microscopy and Raman spectroscopy. Adhesion of the diamond coatings to SiC seal ring substrates was investigated by using overlap polishing with diamond paste or by wear test against Al-12.5%Si alloy. The results show that, after introducing an interposing layer, the internal thermal stresses are reduced so that the adhesion of diamond coatings on the SiC substrates is improved significantly.}, number={2-3}, journal={Surface and Coatings Technology}, author={Fan, W.D. and Jagannadham, K. and Goral, B.C.}, year={1996}, pages={172–182} }
 @article{vispute_narayan_jagannadham_1996, title={Pulsed laser deposition of titanium nitride and diamond-like carbon films on polymers}, volume={25}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029678949&partnerID=MN8TOARS}, DOI={10.1007/BF02666189}, number={1}, journal={Journal of Electronic Materials}, author={Vispute, R.D. and Narayan, J. and Jagannadham, K.}, year={1996}, pages={151–156} }
 @inproceedings{fan_jagannadham_narayan_1996, title={Silicon nitride tools coated with TiC or TiN composite diamond structures}, volume={415}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029753126&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Fan, W.D. and Jagannadham, K. and Narayan, J.}, year={1996}, pages={45–50} }
 @article{vispute_narayan_wu_jagannadham_1995, title={Epitaxial growth of AlN thin films on silicon (111) substrates by pulsed laser deposition}, volume={77}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029307142&partnerID=MN8TOARS}, DOI={10.1063/1.359441}, abstractNote={Aluminum nitride thin films have been grown epitaxially on Si(111) substrates, for the first time, by pulsed laser ablation of sintered AlN target. The influence of process parameters such as laser energy density, substrate temperature, pulse repetition rate, nitrogen partial pressure, etc. on epitaxial growth has been investigated to obtain high quality AlN films. These films were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, x-ray diffraction (Θ and ω scans) technique, high resolution transmission electron microscopy, and scanning electron microscopy. The films deposited at laser energy density in the range of 2–3 J/cm2, substrate temperature of 750 °C, and base pressure of 3×10−7 Torr are single phase and highly oriented along c axis normal to the Si(111) planes. The results of x-ray diffraction and electron microscopy on these films clearly show the epitaxial growth of the AlN films with an orientational relationship of AlN[0001] ∥ Si[111] and AlN[21̄1̄0] ∥ Si[011̄]. The AlN/Si interface was found to be quite sharp without any indication of interfacial reaction. Laser physical vapor deposition is shown to produce high quality epitaxial AlN films with smooth surface morphology when deposited under optimized conditions.}, number={9}, journal={Journal of Applied Physics}, author={Vispute, R.D. and Narayan, J. and Wu, H. and Jagannadham, K.}, year={1995}, pages={4724–4728} }
 @article{raghunathan_chowdhury_fan_jagannadham_narayan_1995, title={Growth of Continuous Diamond Film by Hot Filament CVD Technique on SiC/TiC Pellets, Synthesized Using Combustion Synthesis}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029305151&partnerID=MN8TOARS}, DOI={10.1080/10426919508935045}, abstractNote={Abstract β-SiC/TiC composites were synthesized using the process of self propagating-high temperature combustion synthesis (SHS). The heat released during the exothermic reaction between the metal and the carbon powder results in the melting of silicon and the titanium into which the carbon diffuses and then (3-SiC and TiC precipitates out from the supersaturated solution. The composite was characterized using X-ray diffraction techniques, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. An attempt was made to understand the mechanism of formation of the composite. A theory is proposed for the possible mechanism based on dissolution, diffusion and precipitation from the supersaturated solution. Diamond film was then grown on the pellet by hot filament CVD technique using methane and hydrogen gas as the reactants. The deposition was conducted for a period of four hours. A continuous film of diamond was found to grow on β-SiC/TiC composite using this technique. The diam...}, number={3}, journal={Materials and Manufacturing Processes}, author={Raghunathan, R. and Chowdhury, R. and Fan, W. and Jagannadham, K. and Narayan, J.}, year={1995}, pages={547–558} }
 @inproceedings{raghunathan_chowdhury_jagannadham_narayan_1995, title={Growth of diamond film by CVD on near net shape fabricated β-SiC/TiC composites synthesized using SHS}, volume={365}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029204263&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Raghunathan, R. and Chowdhury, R. and Jagannadham, K. and Narayan, J.}, year={1995}, pages={463–468} }
 @article{narayan_vispute_jagannadham_1995, title={Interfacial processing and adhesion of diamond, diamond-like, and TiN films on metallic and polymeric substrates}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0000793677&partnerID=MN8TOARS}, DOI={10.1163/156856195X00653}, abstractNote={Diamond, diamond-like, and titanium nitride (TiN) films have extremely desirable chemical, electrical, and mechanical properties for a variety of applications ranging from corrosion- and erosion-resistant coatings to electronics packaging of microelectronic devices. However, many of these applications are limited by the poor adhesion of these films to metal and polymer substrates. The adhesion of a film is determined primarily by internal stresses in the film, thermal and lattice mismatch, and most importantly by interfacial bonding. We have developed methods based on mechanical interlocking, chemical bonding, grading of interatomic potentials, and the multilayer discontinuous thin films approach to control stresses and strains in thin films. A substantial improvement in adhesion and wear properties is obtained by using these methods selectively. We review issues related to the adhesion of diamond, diamond-like carbon, and TiN films on metal and polymeric substrates.}, number={6}, journal={Journal of Adhesion Science and Technology}, author={Narayan, J. and Vispute, R.D. and Jagannadham, K.}, year={1995}, pages={753–767} }
 @inproceedings{fan_jagannadham_narayan_1995, title={Modeling of thermal stresses in composite diamond coatings and mechanisms of improvement of adhesion}, volume={356}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029234594&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium - Proceedings}, author={Fan, W.D. and Jagannadham, K. and Narayan, J.}, year={1995}, pages={847–852} }
 @article{godbole_jagannadham_narayan_1995, title={Nucleation and growth of diamond films on aluminum nitride coated nickel}, volume={67}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0000917124&partnerID=MN8TOARS}, DOI={10.1063/1.114527}, abstractNote={We have studied nucleation and growth characteristics of diamond on nickel with AlN buffer layers. The diamond deposits on partially filled 3-d shell transition metals such as Ni, Fe, and Co usually result in the formation of interposing graphite layers which cause poor adhesion of diamond overlayers. To minimize and preferably eliminate the formation of the interposing graphite layer, we coated nickel substrate with ∼1000 Å thick AlN layer by using pulsed laser deposition and subsequently, subjected them to diamond deposition by hot filament chemical vapor deposition method. It is found that the aluminum nitride layer plays a crucial role in limiting carbon diffusion and inhibiting the formation of graphitic carbon and simultaneously enhancing the nucleation and adhesion of diamond phase.}, journal={Applied Physics Letters}, author={Godbole, V.P. and Jagannadham, K. and Narayan, J.}, year={1995}, pages={1322} }
 @article{raghunathan_chowdhury_jagannadham_narayan_1995, title={Synthesis of Highly Dense β-SiC Pellet by Self Propagating High Temperature Synthesis}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029309564&partnerID=MN8TOARS}, DOI={10.1080/10426919508935046}, abstractNote={Abstract β-SiC has been synthesized using the process of self-propagating high temperature synthesis (SHS) (1). Ti was added as a binder and the effect of titanium addition on the reaction propagation has been studied. Temperature of combustion is considerably lowered by the addition of titanium and the incubation period leading to the melting of the silicon powders is reduced. The reaction propagated through the pellet faster and the product synthesized was dense and compact. The synthesized composite was characterized using X-ray, Raman spectroscopy, SEM and TEM. We proposed a model for the synthesis based on dissolution, diffusion and precipitation from the supersaturated solution. There was no indication of the formation of TiSi2, during synthesis. An attempt is made to explain this observation based on free energy considerations.}, number={3}, journal={Materials and Manufacturing Processes}, author={Raghunathan, R. and Chowdhury, R. and Jagannadham, K. and Narayan, J.}, year={1995}, pages={559–563} }
 @article{fan_wu_jagannadham_goral_1995, title={Wear resistant diamond coatings on alumina}, volume={72}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029294275&partnerID=MN8TOARS}, DOI={10.1016/0257-8972(94)02345-X}, abstractNote={Abstract Wear resistant diamond coating systems on alumina substrates with improved adhesion have been developed. These systems consist of single layer diamond coatings and multilayer composite diamond coatings. The multilayer diamond coating systems are made up of an embedding intermediate layer of TiC or TiN or TiCTiN deposited by laser physical vapor deposition on a first layer of diamond. A second layer of diamond is also deposited on the embedding layers. Scanning electron microscopy and Raman spectroscopy have been used to characterize the coatings. Adhesion and wear resistance of the coatings have been tested using an indentation test and an overlap polishing test. The improvement in adhesion of the composite diamond coatings with TiC embedding layer is found to be highest. Mechanisms of the adhesion and wear resistance improvement of the composite films are investigated. The improvement in adhesion is explained by the epitaxial growth of TiC on alumina, TiC and CC bondings between TiC and diamond, the small difference in the thermal expansion coefficients between TiC and alumina, and the close matching of lattice constants between TiC and diamond.}, number={1-2}, journal={Surface and Coatings Technology}, author={Fan, W.D. and Wu, H. and Jagannadham, K. and Goral, B.C.}, year={1995}, pages={78–87} }
 @article{fan_chen_jagannadham_naravan_1994, title={Diamond-ceramic composite tool coatings}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028542013&partnerID=MN8TOARS}, DOI={10.1557/JMR.1994.2850}, abstractNote={We have developed multilayer composite diamond coatings with improved adhesion and wear resistance on WC(Co) tool substrates. The coatings consist of a first layer of discontinuous diamond crystallites that are anchored to the WC(Co) substrate by an interposing layer of ceramic films. These films consist of TiC, TiN, SiC, Si3N4 or WC deposited to provide a conformal coverage on the first layer of diamond. A second or final layer of continuous diamond film is deposited to provide the cutting edge of the tool. The diamond film in the composite layers is deposited by hot filament chemical vapor deposition (HFCVD) and the interposing layer is deposited by laser physical vapor deposition (LPVD). The different parameters associated with the deposition of diamond and interposing layers are optimized to improve the adhesion and wear resistance. We have studied the adhesion characteristics by indentation tests in which the critical load for peeling of the diamond films is determined. Adhesion and wear resistance of the films are also tested using an overlap polishing on diamond paste with 5–6 μm particle size. The diamond and interposing layers in the composite are characterized by scanning electron microscopy and Raman spectroscopy. Results of improvement in adhesion and wear resistance are correlated with the quality of the diamond film and the interposing layer. Better accommodation of thermal stresses and strains in the composite layers has been shown to be responsible for improvement in the adhesion and wear resistance of the composite diamond films.}, number={11}, journal={Journal of Materials Research}, author={Fan, W.D. and Chen, X. and Jagannadham, K. and Naravan, J.}, year={1994}, pages={2850–2867} }
 @article{jagannadham_narayan_chowdhury_tsvetanka_tiwari_1994, title={Domain epitaxial growth of TiN/Si(001), TiN/GaAs(001), and Si/TiN/Si(001) heterostructures by laser physical vapor deposition: Theory and experiment}, volume={23}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028514149&partnerID=MN8TOARS}, DOI={10.1007/BF02655356}, number={9}, journal={Journal of Electronic Materials}, author={Jagannadham, K. and Narayan, J. and Chowdhury, R. and Tsvetanka, Z. and Tiwari, P.}, year={1994}, pages={861–874} }
 @article{zheleva_jagannadham_narayan_1994, title={Epitaxial growth in large-lattice-mismatch systems}, volume={75}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-14744272723&partnerID=MN8TOARS}, DOI={10.1063/1.356440}, abstractNote={Epitaxial growth in the TiN/Si and TiN/GaAs metal-semiconductor systems with a large lattice mismatch was investigated. The orientation relationships have been found to be 〈001〉TiN∥〈001〉Si for TiN growth on Si(001) and [001]TiN∥[110]GaAs and [11̄0]TiN∥[1̄10]GaAs for TiN growth on GaAs(001). The epitaxial growth is characterized by domain epitaxial orientation relationships with m lattice constants of epilayer matching with n of the substrate and with a small residual domain mismatch present in the epilayer. This residual mismatch is responsible for a coherent strain energy. The magnitude of compression of Ti—N bond in the first atomic layer, contributing to the chemical free energy during the initial stages of growth, is found to be a very important factor in determining the orientation relationship. This result was used to explain the differences in the orientation relationships between TiN/Si and TiN/GaAs systems. The various energy terms associated with the domain epitaxial growth are evaluated to illustrate that the domain epitaxial growth is energetically favorable compared to the lattice-mismatched epitaxial growth. The results of this analysis illustrate that the observed variations in the epitaxial growth are consistent with the minimum energy configurations associated with the domain epitaxial growth.}, number={2}, journal={Journal of Applied Physics}, author={Zheleva, T. and Jagannadham, K. and Narayan, J.}, year={1994}, pages={860–871} }
 @article{narayan_tiwari_jagannadham_holland_1994, title={Formation of epitaxial and textured platinum films on ceramics-(100) MgO single crystals by pulsed laser deposition}, volume={64}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028410509&partnerID=MN8TOARS}, DOI={10.1063/1.111693}, abstractNote={We have investigated the formation of textured and epitaxial metallic films on (100) MgO single crystals substrates (lattice constant a=4.21 Å) as a function of deposition temperature during pulsed laser ablation. Platinum (a=3.92 Å) films on MgO with lattice misfit of 7.4% were found to grow epitaxially in the temperature range 500–700 °C. Three-dimensional x-ray diffraction results (theta, phi, and chi scans) show 〈100〉 epitaxy with the alignment of all three cube axes. Rutherford backscattering and channeling measurements on a film deposited at 700 °C showed a minimum yield of 2.2%, which is very close to the defect-free single crystal value. In the temperature range 200–500 °C both 〈100〉 and 〈111〉 textures were observed. The 〈111〉 oriented (normal to the surface) films were random in the plane of the substrate, whereas 〈100〉 crystallites were epitaxial. Below 200 °C, only 〈111〉 crystallites were observed. The 〈111〉 texture of platinum films is also observed when grown on amorphous substrates such as SiO2. The experimental results are normalized with theoretical simulations addressing the minimization of film energy.}, number={16}, journal={Applied Physics Letters}, author={Narayan, J. and Tiwari, P. and Jagannadham, K. and Holland, O.W.}, year={1994}, pages={2093–2095} }
 @inproceedings{fan_jagannadham_narayan_1995, place={Pittsburgh, PA}, series={MRS Online Proceedings Library}, title={Improvement of adhesion of diamond coatings to WC(Co) tool substrates.}, volume={363}, ISBN={9781558992641}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0029227709&partnerID=MN8TOARS}, DOI={10.1557/PROC-363-163}, abstractNote={AbstractAdhesion of diamond coatings to cutting tool substrates is an important property that is needed to replace the polycrystalline diamond tools (PCD) in machine tool applications. The improvement in adhesion of diamond on WC(Co) tool substrates is brought about by formation of a composite layer. Composite layers made up of TiC or TiN and diamond were formed by laser physical vapor deposition of ceramic coatings and hot filament chemical vapor deposition of diamond films. A first layer of discontinuous diamond film on WC is embedded in the ceramic coatings followed by growth of a continuous diamond film that maintains continuity with the first diamond layer. The composite coatings were characterized by SEM and Raman spectroscopy. Adhesion and wear resistance of the diamond coatings were measured using a polishing wear test. The mechanisms of improvement in adhesion were analyzed by finite element modeling. Results show that TiC composite layers improve the adhesion of diamond coatings significantly. This improvement is considered to arise from the modification of the thermal stress at the interface between the diamond film and the WC(Co) tool substrate.}, booktitle={Chemical vapor deposition of refractory metals and ceramics III : symposium held November 28-30, 1994, Boston, Massachusetts, U.S.A.}, publisher={Materials Research Society}, author={Fan, W. D. and Jagannadham, K. and Narayan, J.}, editor={Gallois, B.M. and Lee, W.Y. and Pickering, M.A.Editors}, year={1995}, pages={163–168}, collection={MRS Online Proceedings Library} }
 @article{narayan_raghunathan_chowdhury_jagannadham_1994, title={Mechanism of combustion synthesis of silicon carbide}, volume={75}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0001386542&partnerID=MN8TOARS}, DOI={10.1063/1.356660}, abstractNote={The mechanism of self-propagating high-temperature synthesis (SHS) or combustion synthesis of SiC has been investigated using pellets consisting of silicon and carbon powders. The combustion reaction was initiated by rapidly heating the pellet on a graphite strip. The reaction products were analyzed using scanning and transmission electron microscopy, x-ray diffraction, and Raman spectroscopy. The results show that it is possible to produce β-SiC without any residual silicon and carbon. Occasionally, a very small number density of α-SiC precipitates embedded in the β-SiC matrix was observed. Based upon the microstructural features, it is proposed that the formation of SiC involves the dissolution of carbon into liquid silicon, diffusion of C into liquid silicon, and subsequent precipitation of SiC. The size of the SiC crystallites is determined by the diffusion coefficient of carbon in liquid silicon and the time available for SiC precipitation. The activation enthalpy for the SHS process is estimated to be 59±3 kcal/mol.  }, number={11}, journal={Journal of Applied Physics}, author={Narayan, J. and Raghunathan, R. and Chowdhury, R. and Jagannadham, K.}, year={1994}, pages={7252–7257} }
 @article{jagannadham_narayan_1994, title={Microstructure and properties of high temperature superconducting materials}, volume={26}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028495859&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(94)90157-0}, abstractNote={The properties of high Tc superconducting oxides are correlated with the microstructural features such as point defects, dislocations, and grain boundaries. The magnetic properties of the high Tc superconductors, especially the field vs. temperature, are shown to exhibit different behavior from that of conventional superconductors. The irreversibility line and its significance in flux lattice melting are discussed to highlight the important limitations of the current-carrying capacity of the high Tc superconductors in an applied magnetic field. The mechanisms of flux pinning by oxygen vacancies, dislocations and grain boundaries are described quantitatively. The pinning energies associated with these defects are shown to be small enough that the critical current density cannot be increased considerably at higher temperatures where flux melting takes place. Grain boundaries are shown to be important weak links in the high Tc superconductors. The small coherence length relative to the dimensions of the width of the grain boundary is shown to be responsible for the large reduction in the critical current density associated with the boundaries. The atomic structure of different types of boundary is described in the light of the earlier theories of grain boundaries, and the structural features are shown to be similar. The four important factors contributing to the weak link behavior of the grain boundaries are analyzed and the critical current density associated with the boundaries is derived. The experimental results of the dependence of the critical current density on the misorientation angle, temperature and the magnetic field have been explained based on the grain boundary modelling. More importantly, the spatial dependence of the critical current density around the grain boundary is derived and shown to explain the experimentally observed features.}, number={2-3}, journal={Materials Science and Engineering B}, author={Jagannadham, K. and Narayan, J.}, year={1994}, pages={75–102} }
 @inproceedings{zheleva_jagannadham_biunno_narayan_1994, title={Pulsed laser deposition of epitaxial (110) TiN films on (100) GaAs - processing, characterization and modeling}, volume={317}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028101652&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium Proceedings}, author={Zheleva, Tsvetanka and Jagannadham, K. and Biunno, N. and Narayan, J.}, year={1994}, pages={205–211} }
 @inproceedings{jagannadham_chowdhury_biunno_narayan_1994, title={Raman spectroscopy of TiN films deposited on silicon (001) substrate by laser physical vapor deposition}, volume={317}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028098611&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium Proceedings}, author={Jagannadham, K. and Chowdhury, R. and Biunno, N. and Narayan, J.}, year={1994}, pages={193–198} }
 @inproceedings{zheleva_jagannadham_iamakov_narayan_1994, title={Structural analysis of TiN/Si and TiN/GaAs epitaxial systems by transmission electron microscopy and multi-slice simulation}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0028758447&partnerID=MN8TOARS}, booktitle={Proceedings - Annual Meeting, Microscopy Society of America}, author={Zheleva, Ts. and Jagannadham, K. and Iamakov, V. and Narayan, J.}, year={1994}, pages={858–859} }
 @article{jagannadham_armstrong_hirth_1993, title={Deformation twinning in high-hydrogen-solubility refractory alloy crystals}, volume={68}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-21144472884&partnerID=MN8TOARS}, DOI={10.1080/01418619308221213}, abstractNote={Abstract Deformation twinning was studied in single crystals of three high-hydrogen-solubility refractory alloys; Ta-10 at.% Nb, Nb-10 at.% Mo, and Nb-10 at.% V. The hydrogen concentration was maintained close to 150 p.p.m. by weight. Four different crystal orientations were tested in uniaxial tension and compression; in each case, at four different temperatures: 77K, 142K, 195K and 300K. Trace analyses of the deformation markings were carried out on pairs of perpendicular surfaces to determine the crystallographic nature of slip, twinning, cleavage and hydride precipitates. The sense of the deformation twin shear strains conforms with their occurrence under tensile or compressive stresses for the different crystal orientations. The activation energy for the nucleation of twins is determined by means of dislocation modelling of the twin lamella. It is shown that a stress concentration, either from planar dislocation arrays formed during microslip or from a cleavage crack tip, enables the activation energy...}, number={2}, journal={Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties}, author={Jagannadham, K. and Armstrong, R.W. and Hirth, J.P.}, year={1993}, pages={419–451} }
 @inproceedings{zheleva_jagannadham_narayan_1993, title={Epitaxial growth in large lattice mismatch systems: characteristics of domain epitaxy}, volume={280}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0027884438&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium Proceedings}, author={Zheleva, Tsvetanka S. and Jagannadham, K. and Narayan, J.}, year={1993}, pages={393–398} }
 @inproceedings{zheleva_jagannadham_kumar_narayan_1993, title={Epitaxial growth of TiN on GaAs(100) by pulsed laser deposition}, volume={285}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0027268780&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium Proceedings}, author={Zheleva, Tsvetanka S. and Jagannadham, K. and Kumar, A. and Narayan, J.}, year={1993}, pages={343–348} }
 @inproceedings{chowdhury_chen_jagannadham_narayan_1993, title={Laser processing, characterization, and modeling of epitaxial Si/TiN/Si (100) heterostructures}, volume={285}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0027313965&partnerID=MN8TOARS}, booktitle={Materials Research Society Symposium Proceedings}, author={Chowdhury, Rina and Chen, X. and Jagannadham, K. and Narayan, J.}, year={1993}, pages={501–506} }
 @inproceedings{jagannadham_1993, title={Structure and properties of grain boundaries in high-Tc superconductors}, volume={273}, booktitle={AIP Conference Proceedings}, author={Jagannadham, K}, editor={Narayan, J.Editor}, year={1993}, pages={37–49} }
 @article{jagannadham_narayan_1992, title={Depression of order parameter and effect on grain boundary critical current density}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0026898946&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(92)90120-X}, abstractNote={The depression of the order parameter at grain boundaries in high critical temperature superconducting oxides is determined using two formulations. First, we use the Bardeen-Cooper-Schrieffer formulation and assume formation of Cooper pairs by an attractive interaction potential. The spatial variation of the density of energy states at the Fermi level near the boundary, estimated as a function of hydrostatic stress field, is used to determine the depression of the order parameter. Second, the proximity-effect formulation is used in the form of a boundary condition on the order parameter at the interface. The boundary conditions are solved taking into account the spatial variation of the density of energy states. The depression of the order parameter from the two formulations is used in conjunction with atomic modeling to determine the critical current density associated with the grain boundaries. The model correctly predicts dependence of the critical current density across grain boundaries on the misorientation angle and temperature, in good agreement with experimental observations.}, number={2}, journal={Materials Science and Engineering B}, author={Jagannadham, K. and Narayan, J.}, year={1992}, pages={214–226} }
 @inproceedings{jagannadham_1992, series={MRS Online Proceedings Library}, title={Grain boundary structure and properties of high-TC superconductors.}, DOI={10.1557/PROC-275-597}, abstractNote={ABSTRACTWe have modelled the grain boundaries in high-Tc superconducting oxides and determined the critical current density. The tunneling of superconducting pairs across the coalesced regions is used to determine the boundary effects. The length of the coalesced regions, with continuity of the Cu-O planes maintained by relaxation of the atom positions, is determined by minimization of the energy of the configuration. The depression of the order parameter is evaluated using the continuity conditions at the boundary in the proximity effect formulation. The excess charge distribution at the core of the boundary, determined from the solution to the Poisson's equation, is used to determine the scattering of the superconducting pairs. The width of the boundary, evaluated from modelling, determines the transmission coefficient for tunnelingof superconducting pairs. The critical current density is expressed in terms of these four important factors associated with the grain boundary. All the experimental results are explained by the present modelling of the grain boundary effects.}, booktitle={Layered Superconductors: Fabrication, Properties and Applications}, publisher={Materials Research Society}, author={Jagannadham, K.}, editor={Narayan, JEditor}, year={1992}, pages={597–608}, collection={MRS Online Proceedings Library} }
 @article{jagannadham_narayan_1991, title={A comparative study of grain boundary structure and critical current density in 123-YBaCuO, 2212-BiSrCaCuO and 2223-TlBaCaCuO high temperature superconductors}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0026152154&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(91)90039-X}, abstractNote={Abstract A systematic study of the structure of symmetric and asymmetric tilt boundaries in 123-YBaCuO and 2223-TlBaCaCuO superconductors is carried out using geometrical modelling. The coincidence site lattice (CSL) configurations of the a−b and a−c type grain boundaries with the CSL unit cell are presented and the important differences between them pointed out. The fraction of the continuous superconducting CuO planes and the charge associated with the boundary void configurations are determined as a function of the misorientation angle of the a−b boundaries. Two different orientations in the a−c -type boundaries arising from the interchange of the a and c lattice directions are described. The differences in the a−c -type boundaries in 123-YBaCuO and 2223-TlBaCaCuO are discussed with special reference to the continuity of the CuO planes and the current-carrying capacity. The geometrical modelling is also extended to describe the distortions, the unbalanced charge and the continuity of the CuO planes in the asymmetric tilt boundaries and disclinations in the 123-YBaCuO system. The critical current density associated with the boundaries is studied in terms of tunnelling of superconductor pairs through the coalesced regions containing distortions. The critical current density obtained in terms of the depression of the order parameter, the width and the coalesced region of the boundary is found to agree with the experimental observations. Specifically, the temperature dependence of the critical current density is explained in terms of the variations in the order parameter and the transmission coefficient. Most importantly, the intergrain critical current density is found to decrease with the misorientation angle, which is in good agreement with previous experimental observations.}, number={3}, journal={Materials Science and Engineering B}, author={Jagannadham, K. and Narayan, J.}, year={1991}, pages={201–218} }
 @article{jagannadham_narayan_1991, title={Critical thickness during two-dimensional and three-dimensional epitaxial growth in semiconductor heterostructures}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0026151957&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(91)90024-P}, abstractNote={The homogeneous nucleation of misfit dislocations in two-dimensional and three-dimensional epitaxial structures on rigid substrates was analyzed. It is shown that nucleation and growth of a dislocation in the epilayer involves an activation energy barrier. We propose that this activation energy barrier can be overcome from the residual coherent strain energy in the film. A critical thickness of the epilayer is defined at which a dislocation is nucleated. The activation energy and the coherent strain energy were determined for several different configurations of 60° glide and 90° climb dislocations. The discrepancies that are associated with different formulations are pointed out. Specific numerical calculations were performed for dislocation nucleation in the GaAs/Si system. The results are given in terms of the various energy contributions responsible for nucleation of misfit dislocations, and the critical thickness of the epilayer is evaluated. The critical thickness of the epilayer under the two-dimensional and three-dimensional growth conditions are compared and the results described in terms of the mechanisms of dislocation nucleation.}, number={2}, journal={Materials Science and Engineering B}, author={Jagannadham, K. and Narayan, J.}, year={1991}, pages={107–124} }
 @article{jagannadham_narayan_1991, title={Grain boundary modeling in high critical temperature superconductors}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0026140652&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(91)90014-M}, abstractNote={Geometrical modeling and minimization of energy of grain boundaries in high critical temperature YBaCuO superconducting oxides is used to determine the atomic structure and its influence on the superconducting properties. It is possible to form grain boundaries with four types of atomic planes with different atomic arrangements in the layered structure, thus giving rise to four independent configurations. The structure of the primary coincidence symmetric tilt boundaries containing either a and b or c and a lattice parameters within the grains is illustrated for several misorientations. The modeling is used to determine the fraction of superconducting planes which are continuous across the grain boundary and the excess charge associated with the boundary. The modeling is also applied to secondary coincidence symmetric tilt boundaries and asymmetric tilt boundaries to delineate important features associated with these configurations. The fraction of superconducting planes at the boundaries, which determine their current carrying capacity, is estimated. The relative occupancy of the copper and the oxygen atoms in the coincidence site unit cells is evaluated for each misorientation.}, number={1}, journal={Materials Science and Engineering B}, author={Jagannadham, K. and Narayan, J.}, year={1991}, pages={5–21} }
 @article{rajan_fitzgerald_jagannadham_jesser_1991, title={Misfit accommodation at epitaxial interfaces}, volume={20}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-51649152621&partnerID=MN8TOARS}, DOI={10.1007/BF02665975}, number={7}, journal={Journal of Electronic Materials}, author={Rajan, K. and Fitzgerald, E. and Jagannadham, K. and Jesser, W.A.}, year={1991}, pages={861–867} }
 @article{singh_jagannadham_narayan_1991, title={Nature of textured growth of laser-deposited YBaCuO thin films on (100) MgO}, volume={7}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0026104701&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(91)90006-H}, abstractNote={We have studied, using X-ray and transmission electron microscopy techniques, the texturing of YBa2Cu3O7 superconducting thin films with c axis perpendicular to the lattice-mismatched (100) magnesium oxide substrate. The results were compared with epitaxial growth on the (100) SrTiO3 where the c axis of the film is either perpendicular or parallel to the substrate. Texturing with c axis perpendicular to the substrate occurs as a result of preferential grain growth in the “a” and “b” directions, whereas epitaxial growth involves lattice matching with the underlying substrate. Thin films of YBa2Cu3O7−x were deposited using a pulsed-laser evaporation technique and were further annealed in oxygen to recover the superconducting properties, and to study the nature of textured growth. The grain growth in films was investigated as a function of annealing treatments. The high-temperature annealed films exhibited large textured grains (about 5–10 μm) with c axis perpendicular to the substrate, but the (001) planes were found to be rotated randomly in the plane parallel to the substrate. The low-temperature annealed films showed small grains (≈100 nm) with no preferred texturing. From the microstructural variations between the high- and low-temperature annealed films, the process of grain growth in high-Tc superconducting films was analysed. We propose a model based upon higher mobility of the a-b grain boundaries to explain the texturing of thin films with c axis perpendicular to the substrate.}, number={4}, journal={Materials Science and Engineering B}, author={Singh, R.K. and Jagannadham, K. and Narayan, J.}, year={1991}, pages={287–296} }
 @article{jagannadham_narayan_1991, title={Nucleation of a 60° glide dislocation in two-dimensional or three-dimensional growth of epilayers}, volume={20}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-51649149649&partnerID=MN8TOARS}, DOI={10.1007/BF02665963}, number={7}, journal={Journal of Electronic Materials}, author={Jagannadham, K. and Narayan, J.}, year={1991}, pages={767–774} }
 @article{jagannadham_narayan_1990, title={Critical current density and atomic structure of grain boundaries in high-T<inf>c</inf> superconductors}, volume={61}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0025387628&partnerID=MN8TOARS}, DOI={10.1080/13642819008205516}, abstractNote={Abstract Geometrical modelling of grain boundaries is applied to determine the changes in their atomic structure as a result of atomic relaxation and reconstruction induced by deformation and diffusion processes. The energy associated with the primary and secondary coincidence tilt boundaries in the superconducting Y-Ba-Cu-O oxide is evaluated. The relaxed grain boundary configuration, wherein the surfaces coalesce to maintain continuity of the atomic planes, is obtained by minimization of the total energy of the boundary. The critical current density associated with the grain boundary is determined from the tunnelling behaviour of the superconducting pairs (electrons or holes) across internal boundaries. A quantitative model is presented to express the critical current density associated with the boundary as a function of the misorientation angle and these results are found to be in good agreement with available experimental data.}, number={2}, journal={Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties}, author={Jagannadham, K. and Narayan, J.}, year={1990}, pages={129–146} }
 @article{jagannadham_conrad_1989, title={A two-parameter representation of dynamic dislocation distributions}, volume={113}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024698924&partnerID=MN8TOARS}, DOI={10.1016/0921-5093(89)90307-9}, abstractNote={A two-parameter representation of the dislocation segment length distribution is offered to represent the plastically deformed state of a material. This distribution function represents the radii to which dislocations are bowed during plastic deformation. It is based on the premise that both a minimum and a maximum value of radius exist. Various quantities associated with the plastically deformed state, namely the fraction of mobile dislocations, the stress dependence of strain rate and of the dislocation velocity are derived from the two-parameter distribution function. The distribution function is also applied to the plastic deformation behavior of polycrystalline copper in tension, in torsion and in tension plus torsion. The results illustrate that the two-parameter distribution explains different characteristic features of plastic deformation and also distinguishes the different forms of plastic deformation of solids.}, number={C}, journal={Materials Science and Engineering A}, author={Jagannadham, K. and Conrad, H.}, year={1989}, pages={197–206} }
 @article{jagannadham_narayan_1989, title={Critical thickness during three-dimensional epitaxial growth-A self-consistent approach}, volume={113}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024701108&partnerID=MN8TOARS}, DOI={10.1016/0921-5093(89)90294-3}, abstractNote={Abstract A self-consistent model is developed to describe the formation of misfit dislocation loops in hemispherical epilayers of finite size grown on thick substrates. The lattice mismatch between the substrate and the epilayer is described by virtual interfacial dislocation loops situated in the interface. The free surface boundary conditions are satisfied by the surface dislocation loops situated on the surface of the hemispherical island. A misfit dislocation loop is nucleated and the changes in the energy of the configuration are used to determine if a lowering in the total energy of the configuration can occur. The model consisting of the primatic dislocation loops in the epilayer is replaced by a simpler dislocation model consisting of glide dislocation loops so that the stress fields and interaction energy terms between dislocations in a two-phase medium could be evaluated. The energy associated with the coherent epilayer and that with the misfit dislocation are evaluated by the minimization of the total energy of the configuration with respect to the Burgers vectors of the surface dislocation loops. The position of the misfit dislocation loop from the interface is changed for a given size of the hemispherical island and the energy terms are determined. The formation of a misfit dislocation loop is considered favorable when the energy of the configuration in the presence of the misfit dislocation is lower than that of the coherent epilayer. The numerical analysis is carried out for hemispherical islands of GaAs grown on (100) Si with a misfit dislocation of Burgers' vector 3.84 A. It has been found energetically favorable to nucleate a misfit dislocation loop at a distance of 3 A from the interface when the radius of the hemispherical island is equal to or greater than 40 A. In addition, a misfit dislocation loop could be nucleated at a larger distance from the interface when the size of the epilayer is larger. The results are interpreted in terms of the favorable position for nucleation of the misfit dislocation and its glide motion towards the interface.}, number={C}, journal={Materials Science and Engineering A}, author={Jagannadham, K. and Narayan, J.}, year={1989}, pages={65–73} }
 @article{jagannadham_pollock_wilsdorf_1989, title={Dislocation cell size in a spatially varying stress field of a crack tip region}, volume={113}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024702294&partnerID=MN8TOARS}, DOI={10.1016/0921-5093(89)90324-9}, abstractNote={The spatially varying crack tip stress field is used to determine the dislocation density in the plastic zone. The rearrangement of dislocations is formulated using the minimization of the total energy of the configuration to form the cell structure in the presence of the spatially varying crack tip stress field. The equilibrium dislocation cell size is obtained for the lowest total energy of the configuration which consists of the self-energy and interaction energy terms associated with the dislocations within the cell walls and the work done by the crack tip stress field on the rearrangement of dislocations. A crack along (001) with two equally inclined {111} slip planes giving rise to a cell structure is analyzed. The results obtained using the crack tip stress field to generate a plastic zone without general yield illustrate that the cell size increases with increasing radial distance from the crack tip and increasing difference in the angular orientation from planes of maximum shear stress. It is further found that dislocation cell walls should align themselves on surfaces with constant shear stress. Experimental observations in beryllium foils, several microns thick and deformed in situ in the tensile stage of a high voltage microscope, are presented to show the validity of low energy configurations determined analytically.}, number={C}, journal={Materials Science and Engineering A}, author={Jagannadham, K. and Pollock, T.C. and Wilsdorf, H.G.F.}, year={1989}, pages={373–383} }
 @article{jagannadham_narayan_1989, title={Fracture behavior of laser-modified ceramic materials}, volume={7}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024305382&partnerID=MN8TOARS}, DOI={10.1016/0167-577X(89)90014-1}, abstractNote={The healing of surface cracks in laser surface modified ceramic materials is analyzed. A partial or complete welding of the crack surfaces as a result of laser surface modification of silicon carbide with nickel overlayer is shown to be effective in improving the fracture toughness. The presence of the coherent second phase of nickel changes the nature of applied stress on the crack surfaces and welds the crack tip. Dislocation modelling of the partially closed crack surfaces is presented along with the development of constitutive energy equations associated with the crack in the two-phase medium. Crack configurations under either an applied tensile stress or an antiplane strain condition are analyzed and the results compared. These results show that the critical size of the crack at the interface in the laser surface modified materials is always larger than that of the surface crack. This leads to an improvement of fracture toughness, consistent with experimental observations.}, number={9-10}, journal={Materials Letters}, author={Jagannadham, K. and Narayan, J.}, year={1989}, pages={303–315} }
 @article{jagannadham_armstrong_hirth_1989, title={Low energy cleavage fracture associated with the hydrogen embrittlement of refractory metal alloys}, volume={113}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024701756&partnerID=MN8TOARS}, DOI={10.1016/0921-5093(89)90322-5}, abstractNote={Three dislocation models are investigated for explaining the hydrogen embrittlement of refractory (b.c.c.) metal alloy single crystals and large-grain polycrystals on the basis of cleavage initiation. The models considered are: (1) stress-induced dislocation pile-ups and dislocation reactions; (2) hydrogen-enhanced decohesion of slip plane pile-ups and planar dislocation arrays; and (3) slip and hydrogen interactions with lineage subgrain boundaries. Emphasis is given in each case to the crystallographic features of low strain cleavage initiations in the presence of hydrogen as observed in three refractory alloy systems. Electron microscope observations, including the occurrence of deformation twinning, are presented for the hydrogen-charged materials as a function of strain. Cumulative (low energy) stress fields are described for the dislocation pile-ups and the lineage boundaries. The enhancement of hydrogen concentration in the presence of the stress fields of these dislocation configurations is determined. The slip-twinning relationship and cleavage associated with hydride microprecipitates are considered.}, number={C}, journal={Materials Science and Engineering A}, author={Jagannadham, K. and Armstrong, R.W. and Hirth, J.P.}, year={1989}, pages={339–366} }
 @article{jagannadham_narayan_1989, title={Mechanisms of Improvement of Fracture Strength in Laser‐Surface‐Modified Ceramics}, volume={72}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0346453318&partnerID=MN8TOARS}, DOI={10.1111/j.1151-2916.1989.tb09706.x}, abstractNote={Three mechanisms of improvement in fracture strength of laser‐surface‐modied ceramic materials are proposed to explain the experimental observations of more than 50% increase in fracture strength. First, the improvement in fracture strength by about 50% is considered to arise from either a complete or partial closure of crack surfaces at the interface of the laser‐modified overlayer. The second mechanism of improvement in fracture strength is derived from the physical displacement of the crack tip away from the free surface when a laser‐modified layer is introduced. Thus, the critical crack size, defmed as a crack that propagates with decreasing energy, is increased almost 100%. The Wid mechanism is based upon the compressive stresses introduced in the laser‐modified region. The fast cooling rates attained after laser irradiation are responsible for development of regions of compressive internal stresses. These sources of improvement in fracture strength are analyzed and the results of the calculations compared with experimental results. Through the present understanding of the mechanisms of improvement in fracture strength, it has become possible to calculate a critical thickness of the laser‐modifed layer. It is concluded that the possible improvement of fracture strength is achieved when the thickness of the laser‐modified overlayer is equal to or greater than this critical value.}, number={7}, journal={Journal of the American Ceramic Society}, author={Jagannadham, K. and Narayan, J.}, year={1989}, pages={1185–1191} }
 @inproceedings{narayan_singh_singh_krishnaswamy_jagannadham_lee_prasad_parikh_1989, place={Warrendale, Pa.}, series={Proceedings of the 1989 Symposium}, title={Microstructure and in-situ processing of epitaxial high-Tc films}, booktitle={High temperature superconducting compounds : processing & related properties : proceedings of the 1989 Symposium on High Temperature Superconducting Oxides--Processing & Related Properties, which was sponsored by the Superconducting Materials Committee and held in Las Vegas, NV, February 27 and 28, 1989, at the 118th Annual Meeting of the Minerals, Metals & Materials Society}, publisher={The Metallurgical Society Inc}, author={Narayan, J. and Singh, R.K. and Singh, A.K. and Krishnaswamy, J. and Jagannadham, K. and Lee, C.B. and Prasad, R.K. and Parikh, N.R.}, year={1989}, pages={337–358}, collection={Proceedings of the 1989 Symposium} }
 @article{narayan_sharan_singh_jagannadham_1989, title={Misfit dislocations in superconducting thin films on SrTiO<inf>3</inf>{010}}, volume={2}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024641446&partnerID=MN8TOARS}, DOI={10.1016/0921-5107(89)90009-3}, abstractNote={We have studied the nature of strain-induced dislocations during epitaxial growth of YBa2Cu3-O7−δ films on SrTiO3{010} substrate. From the contrast analysis under different diffraction vectors, it was determined that the dislocations of a[110] and [011] Burgers vectors are formed in (110) and (011) planes respectively. At the points of intersection, they react (a[110]+a[011]→a[101]) to form a[101] segments in (010) planes. We have analyzed the formation of dislocations near the free surface above a critical thickness to minimize the total energy of the system. The dislocations glide into the film and the substrate. The importance of these results in the fabrication of thin film superconducting devices is emphasized.}, number={4}, journal={Materials Science and Engineering B}, author={Narayan, J. and Sharan, S. and Singh, R.K. and Jagannadham, K.}, year={1989}, pages={333–337} }
 @article{jagannadham_wilsdorf_1989, title={Modeling the temperature rise at the tip of a fast crack}, volume={80}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024749727&partnerID=MN8TOARS}, number={10}, journal={Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques}, author={Jagannadham, Kasi and Wilsdorf, Heinz G.F.}, year={1989}, pages={698–709} }
 @article{jagannadham_narayan_1989, title={Modelling of microstructural features in Y-Ba-Cu-O superconductors}, volume={59}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024666627&partnerID=MN8TOARS}, DOI={10.1080/01418618908209828}, abstractNote={Abstract We have investigated characteristics of four important microstructural features, namely, grain boundaries (small-and large-angle), twins, stacking faults and cracks in high-Tc YBa2Cu3O7-x superconducting oxides using transmission electron microscopy techniques. A detailed analysis of these microstructural features is carried out to understand their effect on the superconducting properties, mechanical properties and their environmental sensitivity. An atomic model of the small-angle and large-angle grain boundaries in these superconducting oxides is provided using a geometric description. Some important differences between the grain-boundary structure of the superconducting oxides and that of metals have been identified. The environmental sensitivity of the superconducting oxide is explained in terms of the atomic structure of dislocations associated with the grain-boundary configurations. The strain energy associated with the twinned regions and oriented domains is determined using discrete dislo...}, number={5}, journal={Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties}, author={Jagannadham, K. and Narayan, J.}, year={1989}, pages={917–937} }
 @inproceedings{jagannadham_kunze_meyer_wilsdorf_1989, place={Raleigh, NC, United States}, title={The development of high temperatures in titanium alloys during fast fracture}, volume={3}, DOI={10.1016/B978-0-08-034804-9.50173-X}, abstractNote={A titanium alloy, Ti-10V-2Fe-3Al, was fractured in tensile loading at strain rates between 70 sec-1 and 103 sec-1. Fracture surfaces were investigated by scanning electron microscopy showing in all specimens areas characterized by a deterioration of the normal dimple structure. A computer model was developed that is capable of showing a large temperature increase at the fast moving crack tip. An additional temperature rise due to the rupture of micro-ligaments can bring the localized temperature under certain conditions above the melting point of the alloy at the moment of final separation.}, booktitle={Strength of Metals and Alloys (ICSMA 8)}, publisher={Department of Material Science & Engineering, North Carolina State University}, author={Jagannadham, K. and Kunze, H.-D. and Meyer, L.W. and Wilsdorf, H.G.F.}, year={1989}, pages={1095–1100} }
 @article{narayan_sharan_1988, place={Raleigh, NC, United States}, title={Critical phenomenon and segregation behavior at interfaces and subgrain boundaries}, volume={49}, DOI={10.1051/jphyscol:1988595}, abstractNote={We have analyzed two important phenomena in lattice mismatched systems : (1) critical stresses, strains and thicknesses, and (2) dopanthmpurity segregation at coherent, semicoherent, incoherent interfaces and subgrain boundaries. During formation of epitaxial films, the growth (pseudomorphic) occurs upto a certain thickness with planar spacing normal to the interface being essentially the same both in the substrate and the film. Above a critical thickness it becomes energetically favorable for the film to contain dislocations. This occurs usually by generating glide dislocations near the free surface because there is a lack of dislocation sources in mostly "defect-free" semiconductor materials. We present an analysis of the critical phenomena in semiconductors based upon this experimental fact. In previous work, the critical step associated with the generation of dislocations was largely neglected. We also consider finite (island) growth of thin films and its effect on critical phenomena. The experimental results clearly show the presence of glide dislocations in GeISi and GaAs/Si systems with extra half planes being in the silicon substrate. If the growth or processing temperature is high enough, then the diffusion and segregation phenomena at dislocation arrays and interfaces become important. The interaction of dopants and impurities with dislocation arrays and interfaces results in a drift term in the diffusion equation, which leads to enhanced segregation of dopants and impurities. Such segregation effects are analyzed for GeISi and GaAsISi interfaces as well as subgrain boundaries in silicon. INTRODUCTION Fundamental considerations involved in the formation of thin epitaxial films include misfit strains and segregation behavior at coherent, semicoherent and incoherent interfaces. The critical thickness is defined as the film thickness above which it becomes energetically favorable for a thin film to contain dislocations. The misfit strains in lattice mismatched systems result in a drift term in the diffusion equation which can lead to enhanced diffusion. The generation of dislocations and subsequent precipitation or segregation at the interfaces and dislocation arrays degrade junctions and produce undesirable effects in device processing. Fig. 1 shows epitaxial (pseudomorphic) growth of Ge on (100) Si single crystals, where tha lattice constant of Ge (5.658 A) is about 4.2 % larger than that of Si (5.43 A). No dislocations are observed upto a thickness of about 40 A, as shown in Fig. l(a), however, dislocations with extra half planes are observed in a 60 A thick Ge layer as shown in Fig. l(b). Fig. l(c) illustrates epitaxially grown film of GaAs on silicon substrate and the presence of misfit dislocations in the film. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1988595 C5-732 JOURNAL DE PHYSIQUE The bulk GaAs has roughly 4% higher lattice constant (5.65 A) compared to that of Si (5.43 A). Most of these dislocations are generated at the free surface and move towards the interface to minimize the strain energy of the system. A small fraction of the dislocations is related to the growth processes in these films. High-resolution image of the interface shows presence of dislocations and twins. This paper focuses on the formation of defects and dislocations during the growth of epitaxial films and segregation behavior of dopants at dislocation arrays and interfaces. For lattice mismatched systems the oontrol of number density of dislocations to below lo4 16 cm-2 is required to fabricate advanced senliconductor devices. The segregation of impurities and dopants becomes an important consideration at temperatures, where diffusion associated with stress fields of dislocation arrays and interfaces becomes significant. The dopants are not only lost electrically, once precipitated out, but the precipitates can also act as recombination centers for carriers in the electrically active regions. Fig. 2 illustrates the precipitation of antimony at the dislocations in sb+ implanted and subsequently annealed (001) Si specimens. The ion implantation and annealing result in thin epitaxial layers with cc~mpressive stresses when antimony occupies substitutional sites. The micrograph clearly shows the effectiveness of dislocations in precipitation behavior, which essentially results in bimodal distribution G€ precipitates. The larger precipitates are associated with the dislocations as a result of enhanced diffusion along the dislocation while the smaller precipitates grow in the lattice involving lattice diffusion, homogeneous nucleation and growth. It should be pointed out that some of the large precipitates are not comected via dislocations because the dislocations associated with them are out of contrast for the particular diffraction conditions used. Another characteristic of the large precipitates is the unifomlity of their size, indicating the Oswald ripening phenomenon of the precipitates along the dislocations. The results on precipitation of boron implanted and thermally annealed (001) Si specimens are shown in Fig. 3. The boron atom is an undersize atom in silicon by the same amount as antimony is an oversize alom The boron atoms in substitutional sites in silicon create tensile stresses in the film. In this case, boron concentration is enhanced at the dislocations, but not to the same extent as the enhancement of the antimony concentration. This may point to difficulty in Oswald ripening of boron precipitates as a result of solid state diffusion. On the other hand, since antimony precipitates are in liquid state Oswald ripening seems to be more effective compared to that of boron precipitates in silicon. The critical thickness is determined after considering the activation energy required to nucleate a lattice misfit t i i slocation at the free surface and for it to glide under the stress field associated with a coherent interface. The self and interaction energy terms associated with the dislocation configuration in the finite epilayer are obtained by satisfying the free surface boundary conditions. Thus, the present analysis eliminates all the approximations associated with earlier determinations of critical thickness [I-'!]. Specifically, the stress field due to an interface between an epilayer of finite thickness and an infinitely thiclk subsmte, either coherent or semicoherent, is calculated using the discrete dislocation analysis. The elastic distortion in the system arises due to the difference in lattice parameters of the epilayer and the substrate. The stress field associated with the distortion is a function of the elastic moduli of the epilayer and the substrate. It has been shown that the distortion associated with any source of stress in a solid can be represented in terms of two sets of surface dislocations with mutually orthogonal Burgers vectors [8,9]. Furthermore, the free surface boundary conditions, namely that the tractions on the surface be zero, are satisfied by the disaibution of the surface dislocation array. The discrete dislocation method to determine the distribution of the surface array uses, instead of force equilibrium, a more general approach wherein minimization of the energy of the configuration described in terms of sets of dislocations is used. This method can be made significantly accurate when the minimization of the energy of the configuration is d e d out with respect to both the positions and the Burgers vectors of the dislocations [10]. The advantage of this method lies in its simplicity. It can be employed when the mathematical analysis using the continuous dislocation distribution method becomes extremely tedious as a result of the complex geometry of the configuration under equilibrium. These results are used to determine the critical thickness of the epilayer for nucleation of misfit dislocations. The segregation of dopant atoms in the presence of either a coherent or a partially coherent interface or a grain boundary is analyzed by including the drift forces. When the epilayers are coherent, the drift forces arise only due to configurational energy changes [ l l]. On the other hand, the stress field associated with the dislocation configuration in a partially coherent interface or a grain boundary is responsible for the drift force on the dopant or impurity atom The stress fields obtained by our analysis are used to calculate the interaction energy between an interface and the dopant atom. This interaction energy term is us.& to calculate the drift force [12]. Furthemore, the kinetics of segregation are obtained from the solution to the diffusion equation including the drift tern by an eigen function expansion method. CRITICAL THICKNESS AND ITS IMPORTANCE The possibility of growing high quality epitaxial layers of different materials on lattice mismatched semiconductor substrates is a topic of considerable interest. The range of useful devices available within a given substrate is considerably enhanced by this method. During epitaxial growth if the misfit between a substrate and the growing epilayer is small, the first atomic layers which are deposited will be strained to match the substrate lattice and a coherent interface is formed. However, as the thickness of the growing epilayer increases, the homogeneous strain energy of the epilayer becomes large enough to make the nucleation of misfit dislocations energetically favorable. The thickness of the epilayer at which misfit dislocations will be nucleated to relieve the homogeneous strain energy corresponds to the critical thickness for the system. The existence of the critical thickness was first considered by Van der Merwe [1,2] and later by numerous authors including Matthews et. al. [3-51 and People and Bean [6,7]. Van der Merwe [2] initially determined the critical thickness of a lattice mismatched epilayer by equating the areal strain energy density in the Nm with th}, number={C-5}, journal={Journal de Physique Colloque}, publisher={Department of Material Science & Engineering, North Carolina State University}, author={Narayan, J. and Sharan, S.}, year={1988}, month={Oct}, pages={731–767} }
 @inproceedings{jagannadham_narayan_1988, series={MRS Online Proceedings Library}, title={Critical thickness for three-dimensional epitaxial island growth}, ISBN={9781107410855}, booktitle={Thin Films: Stresses and Mechanical Properties Symposium}, publisher={Materials Research Society}, author={Jagannadham, K and Narayan, J.}, editor={Bravman, J.C. and Nix, W.D. and Barnett, D.M. and Smith, D.A.Editors}, year={1988}, pages={191–198}, collection={MRS Online Proceedings Library} }
 @inproceedings{narayan_singh_jagannadham_1988, title={Laser processing of advanced ceramics}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024128746&partnerID=MN8TOARS}, author={Narayan, J. and Singh, R.K. and Jagannadham, K.}, year={1988}, pages={1–24} }
 @article{singh_jagannadham_narayan_1988, title={Laser surface modification of metal-coated ceramics}, volume={3}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0024106257&partnerID=MN8TOARS}, DOI={10.1557/JMR.1988.1119}, abstractNote={Pulsed excimer laser radiation has been successfully employed in the improvement (> 50%) of fracture strength of metal-coated ceramics. Thin metallic layers (∼500 Å) of nickel were deposited on silicon nitride and silicon carbide substrates and further irradiated with pulsed excimer (xenon chloride, krypton fluoride) laser pulses. The laser energy density was varied from 0.4 to 2.0 J cm −2 to optimize the formation of mixed interfacial layers. The formation of interfacial layers was studied by transmission electron microscopy and Rutherford backscattering spectrometry techniques. Detailed heat flow calculations using implicit finite difference methods were performed to simulate the effects of intense laser irradiation on metal-coated ceramic structures. Three different mechanisms were found to play an important role in the improvement in the fracture strength of these ceramics. Theoretical calculations showed that the displacement of the crack tip away from the free surface by laser surface modification can lead to a 100% improvement in the fracture strength of the ceramic.}, number={6}, journal={Journal of Materials Research}, author={Singh, R.K. and Jagannadham, K. and Narayan, J.}, year={1988}, pages={1119–1126} }
 @article{jagannadham_1987, title={Deformation and fracture behavior of niobium-10 at % vanadium alloy with hydrogen}, volume={22}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023591139&partnerID=MN8TOARS}, DOI={10.1007/BF01132016}, number={12}, journal={Journal of Materials Science}, author={Jagannadham, K.}, year={1987}, pages={4251–4266} }
 @article{jagannadham_laabs_1987, title={Dislocation substructure in in situ deformed foils of niobium-8 to 10 at % vanadium alloy - Part 2}, volume={22}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023310728&partnerID=MN8TOARS}, DOI={10.1007/BF01103516}, number={3}, journal={Journal of Materials Science}, author={Jagannadham, K. and Laabs, F.C.}, year={1987}, pages={818–825} }
 @article{narayan_jagannadham_1987, title={Effect of free surface and interface on thermal annealing of dislocation loops in silicon}, volume={62}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0041716196&partnerID=MN8TOARS}, DOI={10.1063/1.339594}, abstractNote={The denuded zones free from dislocation loops formed near a free surface or an interface in ion-implanted specimens subjected either to rapid thermal annealing or annealing in a furance were studied. The point defects cluster to form dislocation loops. Smaller dislocation loops coalesce by glide and climb processes to form bigger loops. Free surfaces and interfaces give rise to interaction with the dislocation loops, thus exerting an image force. Transmission electron microscopy observations in the annealed specimens are presented to show that dislocation loops situated within twice the diameter from the free surface are annealed out, thus creating a denuded zone. In order to explain the formation of denuded zones, we have analyzed the forces of interaction between a square dislocation loop and either a free surface or a second phase with a planar interface including the Poisson’s ratio effects. The elastic field of a square loop is a reasonable approximation to represent the actually observed circular loop. Analytical closed-form expressions for the stress and displacement fields associated with a square dislocation loop in a two-phase medium are used to calculate the image force acting on the dislocation loop. Further considerations of the equilibrium of the dislocation loop under the action of the image force exerted by the free surface and the opposing lattice frictional stress at the annealing temperature enable us to determine the dimensions of the denuded zone that are found to be in agreement with the experimental results. These results further show that a soft second phase (over layer) attracts the dislocation loops whereas a hard second phase repels them.}, number={5}, journal={Journal of Applied Physics}, author={Narayan, J. and Jagannadham, K.}, year={1987}, pages={1694–1697} }
 @inproceedings{jagannadham_narayan_1987, title={Effect of free surfaces and interfaces on dopant distribution profiles}, volume={91}, DOI={10.1557/proc-91-81}, abstractNote={ABSTRACTThe drift force exerted by a free surface, a coherent or a noncoherent interface on dopant atoms has been analyzed. We have considered a coherent or a noncoherent interface present in an epilayer of finite thickness. The difference in the shear modulus of the matrix and of the second phase is responsible for the configurational energy of a dopant atom in a coherent two-phase medium. On the other hand, the hydrostatic component of stress associated with a misfit dislocation in a noncoherent interface gives rise to a first-order size interaction. The drift forces are responsible for dopant diffusion towards a free surface or an interface. The diffusion equation including the drift term is solved using an eigen function expansion method with appropriate boundary conditions. The concentration profiles obtained from the analysis of the diffusion equation are in qualitative agreement with those obtained experimentally. The attractive drift force gives rise to a peak in the dopant concentration at the interface followed by a minimum near the interface. These calculations and the observed concentration profiles enable us to evaluate the interaction energy term of the dopants with free surfaces and interfaces and the dilatation associated with the point defects.}, booktitle={MRS Online Proceedings Library}, publisher={Materials Research Society and Cambridge University Press}, author={Jagannadham, K and Narayan, J}, year={1987}, pages={81–90} }
 @article{jagannadham_armstrong_1987, title={Evidence for dislocation pile-ups at grain boundaries from slip band step height observations}, volume={21}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023455660&partnerID=MN8TOARS}, DOI={10.1016/0036-9748(87)90283-3}, abstractNote={Interferometric observations of slip band step heights have been employed to investigate the inhomogeneous plastic deformation properties exhibited by metal crystals (I). Accurate measurements of the slip band step heights have been made more recently to provide information about the early stages of plastic deformation in polycrystals (2,3), particularly relating to the question of whether grain boundaries are sources of dislocations or are obstacles to the movement of dislocations generated within the polycrystal grains. The latter case is an important tenet of the dislocation pile-up explanation for the Hall-Petch relation describing the plastic flow stress dependence on polycrystalline grain size (4). In this article, we demonstrate that the reported interferometric measurements provide reasonably direct evidence for the validity of the dislocation pile-up model.}, number={11}, journal={Scripta Metallurgica}, author={Jagannadham, K. and Armstrong, R.W.}, year={1987}, pages={1459–1462} }
 @article{jagannadham_narayan_1987, title={Modification of dopant profiles due to surface and interface interactions: Applications to semiconductor materials}, volume={61}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-5544266950&partnerID=MN8TOARS}, DOI={10.1063/1.338152}, abstractNote={The kinetics of segregation of dopant solute atoms in the presence of free surfaces and interfaces are analyzed by solving the diffusion equation with a drift term. The drift term includes the configurational interaction energy associated with an oversize or an undersize atom near a coherent interface when the continuity conditions are satisfied. Both an analytical solution and a numerical procedure are provided to solve the problem by eigenfunction expansion method. A new procedure for evaluating the eigenvalues to include higher-order terms is given. It is further established that an attractive force due to either a soft second phase or a free surface gives rise to a minimum in the concentration profile near the interface while a hard second phase results in a monotonically increasing concentration. The position of the minimum in the concentration profile in the presence of a soft second phase or the slope of the concentration profile in the presence of a hard second phase provides a measure of the strength of the defect and the interaction-energy term which can be compared with experimental observations. In particular, we have considered changes in the dopant profiles in silicon under the influence of the free surface, in silicon with silicon dioxide, gallium arsenide, germanium, magnesium oxide and in germanium with silicon, all deposited as a second phase, respectively.}, number={3}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Narayan, J.}, year={1987}, pages={985–992} }
 @inproceedings{narayan_singh_jagannadham_1987, title={SURFACE MODIFICATION AND PROCESSING OF MATERIALS.}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023594488&partnerID=MN8TOARS}, author={Narayan, J. and Singh, R. and Jagannadham, K.}, year={1987}, pages={33–61} }
 @article{jagannadham_wilsdorf_1987, title={Spatially varying crack tip stress fields and low energy dislocation substructures}, volume={34}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023393977&partnerID=MN8TOARS}, DOI={10.1007/BF00013084}, number={4}, journal={International Journal of Fracture}, author={Jagannadham, K. and Wilsdorf, H.G.F.}, year={1987}, pages={297–307} }
 @inproceedings{sharan_jagannadham_narayan_1987, place={New York}, title={Stress distribution and critical thickness of thin epitaxial films}, volume={102}, DOI={10.1557/proc-102-31}, abstractNote={ABSTRACTWe have calculated the stress distribution and critical thickness for the growth of strained epilayers having various values of misfit between the epilayer and the substrate. During formation of epitaxial films, the growth (pseudomorphic) occurs upto a certain thickness with planar spacing normal to the interface being essentially the same both in the substrate and the film. Above a critical thickness it becomes energetically favorable for the film to contain dislocations. This occurs usually by generating glide dislocations near the free surface because there is a lack of dislocation sources in mostly “defect-free” semiconductor materials. We present an analysis of the critical phenomena in semiconductors based upon this experimental fact. In all the previous analyses, the critical step associated with the generation of dislocations was neglected. We also consider finite (island) growth of thin films and its effect on critical phenomena. The experimental results show the presence of glide dislocations in Ge/Si with the extra half planes in silicon substrate.}, booktitle={MRS Online Proceedings Library}, publisher={Materials Research Society and Cambridge University Press}, author={Sharan, S. and Jagannadham, K and Narayan, J}, year={1987}, pages={31–39} }
 @inproceedings{sharan_jagannadham_narayan_1987, place={New York}, title={Stress distribution and critical thicknesses of thin epitaxial films.}, volume={91}, DOI={10.1557/PROC-91-311}, abstractNote={ABSTRACTWe have calculated stress distribution and critical thickness for the growth of strained epilayers having various values of mismatch between the epilayer and the substrate. The present analysis has been carried out assuming that the nucleation of a misift dislocation is controlled by the activation energy. Further, a misfit dislocation is nucleated when the areal strain energy density of the coherent film exceeds the activation energy associated with the misfit dislocation configuration. The latter term has been deternmined using the discrete dislocation method in conjunction with a surface dislocation analysis. The surface dislocation configuration is obtained by minimizing the total energy associated with the two-phase medium. It is verified that the free surface boundary conditions and the continuity of stresses acrosss the interface are satisfied by the surface dislocation array. These energy calculations are expected to be more accurate than those performed by previous workers.}, booktitle={MRS Online Proceedings Library}, publisher={Materials Research Society and Cambridge University Press}, author={Sharan, S and Jagannadham, K and Narayan, J}, year={1987}, pages={311–321} }
 @article{jagannadham_laabs_1987, title={The development of dislocation substructure in hydrogen embrittled niobium-8 to 10 at % vanadium alloy - Part 1}, volume={22}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0023313981&partnerID=MN8TOARS}, DOI={10.1007/BF01103515}, number={3}, journal={Journal of Materials Science}, author={Jagannadham, K. and Laabs, F.C.}, year={1987}, pages={803–817} }
 @article{jagannadham_narayan_1987, title={The elastic field associated with a square dislocation loop in a two-phase medium}, volume={62}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33646114489&partnerID=MN8TOARS}, DOI={10.1063/1.339595}, abstractNote={The surface dislocation analysis of the three-dimensional distortion associated with a prismatic square dislocation loop in a two-phase medium is presented. Closed-form expressions for the stresses and displacements due to the dislocation loop are obtained. These results are used to calculate the image force acting on the dislocation loop either due to a free surface or a second phase with a different shear modulus and Poisson’s ratio. Further, the application of the results to the formation of denuded zones free from dislocation loops in ion-implanted silicon upon thermal annealing are illustrated in terms of the glide movement due to the attractive image force exerted by the free surface.}, number={5}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Narayan, J.}, year={1987}, pages={1698–1703} }
 @article{jagannadham_narayan_1986, title={Elastic strain energy and forces on point defects in a two-phase medium}, volume={1}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0022594898&partnerID=MN8TOARS}, DOI={10.1557/JMR.1986.0193}, abstractNote={Elastic strain energy and forces on point defects in a two-phase medium with a planar interface are analyzed employing the surface dislocation analysis developed earlier for three-dimensional distortions. The important field components, namely, the tractions and the displacements arising due to the point source at the interface, are determined. Furthermore, the field components at the interface are used to determine the elastic strain energy associated with the point source in the two-phase medium and the elastic force exerted by the second phase on the point defect. The significance of these results to the force acting on a vacancy or an interstitial at the interface is emphasized.}, number={1}, journal={Journal of Materials Research}, author={Jagannadham, K. and Narayan, J.}, year={1986}, pages={193–201} }
 @article{jagannadham_wilsdorf_1986, title={Low energy dislocation structures associated with cracks in ductile fracture}, volume={81}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0022767691&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(86)90268-5}, abstractNote={Ductile fracture in metals and alloys is preceded by work hardening and necking. Microstructural processes, previously explored by in situ transmission electron microscopy, have been re-examined in the context of interactions between glide dislocations and crack tips. In this, the parameters which significantly influence experimental findings have been critically reviewed and theoretical aspects of ductile fracture have been examined including the principle of energy minimization. Consideration was given to the displacement of the stress singularity ahead of the crack tip on account of the plastic zone and the effects of thermal instabilities during crack growth. Crack propagation occurs in ductile materials mostly by void coalescence. This requires the nucleation of microcracks ahead of the crack tip as was observed experimentally in agreement with theoretical expectations. Microcrack initiation was seen to take place at dislocation cell walls which represent the most frequently formed low energy dislocation configurations in work-hardened metals. As a consequence, too, the formation of a plastic crack and its grorth in a virgin crystal are distinctly different from the nucleation and growth of a crack in a crystal with a well-defined cell structure that was formed through prior deformation. Dislocation multiplication is considered to take place by the supercritical bowing of the longest free link lengths present within the cell walls, as also observed experimentally. The microstructural changes that take place in the plastic zone ahead of the crack tip are found to be more important in fracture than the microscopic processes immediately at the tip itself.}, number={C}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Wilsdorf, H.G.F.}, year={1986}, pages={273–292} }
 @inproceedings{jagannadham_1986, title={SURFACE DISLOCATION DESCRIPTION OF DISTORTION ASSOCIATED WITH A PLANAR INTERFACE.}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0022909808&partnerID=MN8TOARS}, author={Jagannadham, K.}, year={1986}, pages={51–72} }
 @article{jagannadham_narayan_1986, title={The influence of a planar interface on the energy minimization principle}, volume={81}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0022767251&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(86)90257-0}, abstractNote={A stable dislocation configuration in a homogeneous medium with a free surface boundary satisfies two principles, namely that the total energy associated with the configuration is mininum and that the sum of the Burgers vectors of all the dislocations vanishes. The continuity conditions imposed at the interface in a two-phase medium modify the two principles. A surface dislocation description of the two-phase interface is provided in order to express the continuity conditions at the interface. A set of constitutive energy equations is obtained so that the energy minimization procedure coupled with discrete dislocation analysis can be used to determine the elastic field associated with the two-phase medium. The formulation of the total strain energy of the two-phase medium from the tractions and displacements at the interface is illustrated for either a two-dimensional or a three-dimensional two-phase medium. The application of these ideas to semiconductor processing is discussed.}, number={C}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Narayan, J.}, year={1986}, pages={127–139} }
 @article{jagannadham_narayan_wilsdorf_1986, title={The influence of several parameters on electron microscopic observations of in-situ fracture}, volume={9}, journal={Crystal Properties and Preparation}, author={Jagannadham, K. and Narayan, J. and Wilsdorf, H. G. F.}, year={1986}, pages={1–53} }
 @article{jagannadham_raghavan_1984, title={DISLOCATION CLIMB VIA JOG MOVEMENT AT THE TIP OF A CRACK.}, volume={37}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0021470339&partnerID=MN8TOARS}, number={4}, journal={Transactions of the Indian Institute of Metals}, author={Jagannadham, K. and Raghavan, K.S.}, year={1984}, pages={357–360} }
 @article{jagannadham_1984, title={The elastic stress field associated with a curved dislocation in a two-phase medium with a planar interface}, volume={63}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0021388319&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(84)90164-2}, abstractNote={Abstract The elastic field associated with an infinitestimal dislocation segment situated parallel to a planar interface in one of the phases of a two-phase medium is determined by means of surface dislocation analysis. In particular. the continuity conditions at the interface resulting from the tractions and the displacement gradients due to the elastic field of an infinitesimal segment are satisfied using a continuous distribution of surface dislocations on either side of the interface. The resulting dislocation distributions are used to determine the tractions at the interface. Furthermore, the relation between an interface dislocation and surface dislocations situated in either phase is derived. The significance of these results to structural changes at the interface is emphasized.}, number={1}, journal={Materials Science and Engineering}, author={Jagannadham, K.}, year={1984}, pages={65–80} }
 @article{jagannadham_1983, title={A mechanism of void growth in the region of the plastic zone ahead of a crack-tip}, volume={22}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0020749672&partnerID=MN8TOARS}, DOI={10.1007/BF00960098}, number={1}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1983}, pages={41–63} }
 @article{jagannadham_marcinkowski_1983, title={Discrete dislocation analysis and path dependent plasticity}, volume={18}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0020596176&partnerID=MN8TOARS}, DOI={10.1016/0013-7944(83)90106-6}, abstractNote={Abstract The discrete dislocation method has been applied in order to determine the path dependent plasticity and work hardening associated with the formation of a plastic zone at the tip of a crack in a semi-ductile or ductile material. The constitutive equations connecting the energy terms contributing to the total energy of a plastic crack are derived and the crack extension force, or J integral, is expressed in a simple form in terms of these energy terms. The deficiencies in the continuum mechanical approach in analyzing stably growing cracks under incremental loading conditions are pointed out and the merits of discrete dislocation analysis in overcoming these deficiencies are illustrated. The results of discrete dislocation analysis are used to obtain both a microscopic and macroscopic perspective of the fracture processes.}, number={1}, journal={Engineering Fracture Mechanics}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1983}, pages={171–192} }
 @article{jagannadham_1983, title={Steady state vacancy concentration around a plastic crack}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0020800020&partnerID=MN8TOARS}, DOI={10.1007/BF02654389}, number={8}, journal={Metallurgical Transactions A}, author={Jagannadham, K.}, year={1983}, pages={1615–1624} }
 @article{jagannadham_1983, title={The influence of the crack tip stress field on the nucleation and growth of voids}, volume={60}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0020798775&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(83)90178-7}, abstractNote={The discrete dislocation method is employed to determine the influence of the crack tip stress field on the nucleation and growth of microvoids in the plastic zone. Voids nucleated from both climb-type and glide-type lattice dislocations are considered. In particular, voids in the shear mode parallel to the slip plane and those in the tensile mode either parallel to the crack plane or perpendicular to the slip plane are analyzed to determine the most favorable orientation. The void nucleation and growth leading to the largest decrease in energy or negative energy gradient are chosen as those with the most favorable orientation. The significance that the results have on the experimental observations of the ductile fracture behavior of metals and alloys with respect to void coalescence mechanism is emphasized.}, number={2}, journal={Materials Science and Engineering}, author={Jagannadham, K.}, year={1983}, pages={95–108} }
 @book{jagannadham_marcinkowski_1983, place={Aedermannsdorf, Switzerland}, title={Unified theory of fracture}, ISBN={9780878495238}, publisher={Trans Tech Publications}, author={Jagannadham, K. and Marcinkowski, M. J.}, year={1983} }
 @article{jagannadham_1982, title={Surface dislocation description of three-dimensional distortions in two-phase systems A point force normal to a planar interface}, volume={46}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0020155485&partnerID=MN8TOARS}, DOI={10.1080/01418618208236204}, abstractNote={Abstract The surface dislocation description of a three-dimensional distortion in a two-phase medium with a planar interface is formulated. In particular, the continuity conditions across the planar interface arc satisfied by a continuous distribution of dislocations when a point force normal to the interface is situated in one of the phases. Furthermore, the dislocation distribution functions are derived and the traction component at the interface obtained. The availability of an alternate description of distortion in terms of surface dislocations at the interface is emphasized so that it can be employed advantageously to replace the conventional elasticity methods.}, number={1}, journal={Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties}, author={Jagannadham, K.}, year={1982}, pages={31–39} }
 @article{jagannadham_marcinkowski_1981, title={Discrete dislocation analysis of a plastic crack under repeated loading}, volume={63}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0019392055&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210630139}, abstractNote={The constitutive equations connecting the energy terms which contribute to the total energy of a stable growing crack under repeated stresses are obtained while the crack extension force and the J integral are derived. The energy state of the crack, either loaded or unloaded, is obtained using the discrete dislocation method of analysis. The fatigue crack growth processes are interpreted in terms of the energy of the crack configuration. The results are discussed with particular relevance to experimental observations on fracture surfaces produced under cyclic loading conditions. 
 
 
 
Die grundlegenden Gleichungen die die zur Gesamtenergie eines stabil wachsenden Risses unter wiederholter Belastung beitragenden Energieterme verknupfen, werden erhalten, und die Risverlangerungskraft und das J-Integral werden abgeleitet. Der Energiezustand des Risses, mit oder ohne Last, wird mit der Analysenmethode diskreter Versetzungen erhalten. Der Ermudungsriswachstumsprozes wird mit der Energie der Riskonfiguration interpretiert. Die Ergebnisse werden besonders im Hinblick auf experimentelle Beobachtungen an Bruchflachen bei zyklischer Belastung diskutiert.}, number={1}, journal={physica status solidi (a)}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1981}, pages={299–304} }
 @article{jagannadham_marcinkowski_1980, title={Discrete dislocation analysis of a tensile crack under fatigue}, volume={44}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-49149147544&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(80)90231-1}, abstractNote={The discrete dislocation method is employed to determine the effect of pre-existing crack size on the behavior of a plastic tensile crack under static loading. The behavior of a tensile crack under cyclic and reverse loading is also determined by the same method. Three important steps in the fatigue crack growth during each cycle are identified. It is concluded that the details of the fatigue crack growth during each cycle of loading cannot be inferred from the fatigue striations observed on the crack surfaces after fracture. The statistical nature of fatigue is explained by the range of pre-existing crack sizes present in a material which may or may not contain a crack of critical size that can propagate under cyclic or reverse loading.}, number={1}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1980}, pages={63–72} }
 @article{jagannadham_marcinkowski_1980, title={Discrete dislocation analysis of pre-existing cracks}, volume={16}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0019022299&partnerID=MN8TOARS}, DOI={10.1007/BF00013377}, number={3}, journal={International Journal of Fracture}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1980}, pages={193–206} }
 @article{jagannadham_marcinkowski_1980, title={Further refinements in the energy of grain boundaries}, volume={15}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018997631&partnerID=MN8TOARS}, DOI={10.1007/BF00551718}, number={3}, journal={Journal of Materials Science}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1980}, pages={563–574} }
 @article{jagannadham_marcinkowski_1980, title={Surface dislocation model of a dislocation in a two-phase medium}, volume={15}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018985509&partnerID=MN8TOARS}, DOI={10.1007/PL00020063}, number={2}, journal={Journal of Materials Science}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1980}, pages={309–326} }
 @article{marcinkowski_jagannadham_1979, title={Behavior of finite two-phase bodies in response to internal and external stresses I. Geometrical considerations}, volume={41}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018543835&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(79)90046-6}, abstractNote={The geometry of two-phase interfaces in finite bodies subjected to both internal and external stress has been studied in detail. The two phases comprising the interface have been chosen with differing elastic constants. It has been shown that the continuity of stress and strain across the two-phase interface as well as the stress-free boundary conditions on the free surface can all be satisfied by a suitable distribution of surface dislocations.}, number={1}, journal={Materials Science and Engineering}, author={Marcinkowski, M.J. and Jagannadham, K.}, year={1979}, pages={75–80} }
 @article{jagannadham_marcinkowski_1979, title={Behavior of finite two-phase bodies in response to internal and external stresses II. Numerical considerations}, volume={41}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018544499&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(79)90047-8}, abstractNote={A discrete dislocation method in conjunction with a surface dislocation analysis has been applied to a two-phase body subjected to either an internal stress or an external stress. The analysis can be performed by assuming either that all surface dislocations belong to the two-phase system or that each of the surface arrays belongs to a single phase in which it is located. It has been shown that these two methods are equivalent. The results of the discrete dislocation method are in complete agreement with the method of continuous distribution of dislocations. The geometry of the two-phase body subjected to an internal or external stress illustrated in Part I of the present study has thus been verified. It has been shown that the discrete dislocation method can be employed with relative simplicity when applied to complex geometries associated with a finite two-phase body.}, number={1}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={81–97} }
 @article{jagannadham_marcinkowski_1979, title={Behaviour of an edge dislocation in a semi-infinite solid with surface energy effects}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250262787&partnerID=MN8TOARS}, DOI={10.1007/BF00561288}, number={5}, journal={Journal of Materials Science}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={1052–1070} }
 @article{jagannadham_marcinkowski_1979, title={DISCRETE DISLOCATION ANALYSIS OF GRAIN BOUNDARY ENERGIES.}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018321605&partnerID=MN8TOARS}, number={2}, journal={Cryst Lattice Defects}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={81–94} }
 @article{jagannadham_marcinkowski_1979, title={Discrete dislocation analysis of a plastic shear crack}, volume={15}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018454389&partnerID=MN8TOARS}, DOI={10.1007/BF00037828}, number={2}, journal={International Journal of Fracture}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={119–133} }
 @article{jagannadham_marcinkowski_1979, title={Discrete dislocation analysis of cracks}, volume={52}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018457530&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210520238}, abstractNote={A detailed discrete dislocation analysis is made of the behavior of tensile cracks. This discrete dislocation method minimizes the total energy of the configuration with respect to both the Burgers vector as well as the position of each dislocation. This approach is shown to be somewhat more accurate than those employed earlier. In particular, the present method is compared with the earlier discrete calculations as well as those which employ a single dislocation representation of the plastic zone. 
 
 
 
Es wird mittels einer ausfuhrlichen Analyse diskreter Versetzungen das Verhalten von Dehnungsspalten untersucht. Die Methode diskreter Versetzungen minimalisiert die Gesamtenergie der Konfiguration sowohl bezuglich des Burgersvektors als auch der Lage jeder Versetzung. Es wird gezeigt, das dieses Verfahren etwas genauer ist als die fruher benutzten. Insbesondere wird die Methode sowohl mit den fruheren diskreten Rechnungen als auch mit denen, die eine Darstellung einzelner Versetzungen der plastischen Zone verwenden, verglichen.}, number={2}, journal={physica status solidi (a)}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={663–674} }
 @article{jagannadham_marcinkowski_1979, title={Dislocations, Disclinations, and Grain Boundaries in a Finite Solid}, volume={54}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018506453&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210540237}, abstractNote={An earlier surface dislocation analysis applied to infinite grain boundaries is extended to grain boundaries and disclinations in a finite solid. The coalescence of the grain boundary surfaces is described by grain boundary surface dislocation arrays. The conservation of Burgers vectors is satisfied by the screening dislocation array. Equilibrium positions of the screening array are determined by minimizing the total energy of the configuration. A disclination is described as a grain boundary ending inside a crystal. The differences between the distortion around a disclination and a grain boundary in a finite body are elucidated. The surface dislocation analysis of an elastically bent crystal is given for the first time. A plastically bent crystal is described in terms of regions containing disclinations or grain boundaries surrounded by stress-free surfaces. The stress-free surfaces form a network and cannot end inside the crystal. 
 
 
 
Eine fruhere Oberflachenversetzungsanalyse fur unendliche Korngrenzen wird auf Korngrenzen und Versetzungen in einem endlichen Festkorper ausgedehnt. Die Koaleszenz der Korngrenzenoberflachen wird durch Korngrenzenoberflachen-Versetzungsanordnungen beschrieben. Die Erhaltung des Burgersvektors wird durch die abschirmende Versetzungsanordnung befriedigt. Gleichgewichtslagen der abschirmenden Anordnung werden durch Minimalisierung der Gesamtenergie der Anordnung bestimmt. Eine Disklination wird als Korngrenze, die im Inneren des Kristalls endet, beschrieben. Die Unterschiede zwischen einer Verzerrung um eine Disklination und einer Korngrenze in einem endlichen Korper werden aufgedeckt. Zum erstenmal wird eine Oberflachen-versetzungsanalyse eines elastisch gebogenen Kristalls angegeben. Ein plastisch gebogener Kristall wird mit Bereichen beschrieben, die Disklinationen oder Korngrenzen enthalten, die von spannungsfreien Oberflachen umgeben sind. Die spannungsfreien Oberflachen bildene in Netzwerk und konnen nicht im Inneren des Kristalls enden.}, number={2}, journal={physica status solidi (a)}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={715–727} }
 @article{jagannadham_marcinkowski_1979, title={Relationship between surface tension and energy, interfacial energy and lattice friction}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018492467&partnerID=MN8TOARS}, DOI={10.1007/BF00569294}, number={7}, journal={Journal of Materials Science}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={1717–1732} }
 @article{jagannadham_marcinkowski_1979, title={Surface dislocation model of a finite stressed solid}, volume={38}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018480160&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(79)90130-7}, abstractNote={A surface dislocation model using the discrete dislocation method has been applied to a finite solid subjected to either an applied stress or an internal stress. It has been shown that the state of stress in a finite body can be obtained by isolating the finite body with the aid of the surface arrays of dislocations such that the surface boundary conditions are satisfied on the surfaces of the finite body. The surface dislocations in general consist of two arrays: one whose Burgers vector is large and whose presence on the surface leads to a major relaxation of the surface and one whose Burgers vector is small and whose presence on the surface leads to a minor relaxation of the surface. The surface arrays are determined by minimizing the total energy of the configuration which corresponds to the free surface boundary conditions. The surface dislocation model has been utilized for a finite solid subjected to compression, shear and rotation. It has also been employed for a solid containing either a screw dislocation or an edge dislocation. The advantages of employing the surface dislocation model over other methods are illustrated.}, number={3}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1979}, pages={259–270} }
 @article{jagannadham_marcinkowski_1978, title={Comparison of the image and surface dislocation models}, volume={50}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018030914&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210500135}, abstractNote={The image dislocation model used in satisfying the free surface boundary conditions is found to be physically-unrealistic for various reasons. On the other hand, it is shown that the surface dislocation model is physically realistic in satisfying these boundary conditions. The advantages of the surface dislocation model over the image dislocation model are discussed. The surface dislocation model is described in detail for two fundamental orientations of the Burgers vector of the dislocation with respect to the free surface. The method of continuous distribution of dislocations is used to arrive at the distribution functions. It is also shown that the discrete dislocation method can be used very effectively to replace the continuous distribution method in the evaluation of the surface dislocation distribution. 
 
 
 
Es wird gefunden, das das Bildversetzungsmodell, das zur Befriedigung der Randbedingungen der freien Oberflache benutzt wird, aus verschiedenen Grunden physikalisch unrealistisch ist. Andererseits wird gezeigt, das das Oberflachenversetzungsmodell physikalisch realistisch ist bei der Befriedigung dieser Randbedingungen. Die Vorzuge des Oberflachenversetzungsmodells gegenuber dem Bildversetzungsmodell werden diskutiert. Das Oberflachenversetzungsmodell wird ausfuhrlich fur zwei hauptsachliche Orientierungen des Burgersvektors der Versetzung bezuglich der freien Oberflache beschrieben. Die Methode der kontinuierlichen Verteilung der Versetzungen wird benutzt, um die Verteilungsfunktion zu erhalten. Es wird auch gezeigt, das die Methode der diskreten Versetzung sehr effektiv genutzt werden kann, um die Methode der kontinuierlichen Verteilung bei der Ermittlung der Oberflachenversetzungsverteilung zu ersetzen.}, number={1}, journal={physica status solidi (a)}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1978}, pages={293–302} }
 @article{jagannadham_marcinkowski_1978, title={Continuous plastic cracks in ordered alloys}, volume={13}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018005883&partnerID=MN8TOARS}, DOI={10.1007/BF00548736}, number={8}, journal={Journal of Materials Science}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1978}, pages={1725–1739} }
 @article{jagannadham_marcinkowski_1978, title={Discrete dislocation analysis of a high-temperature crack}, volume={33}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017958433&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(78)90150-7}, abstractNote={A detailed discrete dislocation analysis of the behavior of a high temperature crack has been made. The high temperature tensile crack expands at a constant applied stress by emitting lattice dislocations in order to decrease its energy; otherwise it expands elastically. The lattice dislocations climb away from the crack under the action of the applied stress and the crack tip stress field. The work done by the excess vacancy concentration over the equilibrium value in opposing the dislocation climb is reversible. When the plane of climb of the lattice dislocation is the same as that of the crack plane, crack growth takes place at high energy since the crack pushes all the lattice dislocations during its growth. Thus, all the dislocations should necessarily climb forward. On the other hand, when the climb plane is inclined to the crack plane, the lattice dislocations which are formed at the tip climb forward under the action of the crack tip stress field; however, those remaining behind the tip climb back towards the crack and join the crack to decrease the vacancy concentration. The important difference between a low-temperature plastic crack and that at high temperature lies in the fact that frictional work on glide dislocations is irreversible, while work done on climb dislocations by the excess vacancy concentration is reversible.}, number={1}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1978}, pages={21–33} }
 @article{jagannadham_marcinkowski_1978, title={Dislocation model of the interaction between a tensile crack and a hole}, volume={14}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017958558&partnerID=MN8TOARS}, DOI={10.1007/BF00032542}, number={2}, journal={International Journal of Fracture}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1978}, pages={155–171} }
 @article{marcinkowski_jagannadham_1978, title={The fine structure and energy of grain boundaries}, volume={50}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0018051036&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210500229}, abstractNote={A non-rigid model of a symmetric tilt boundary of arbitrary misorientation is formulated. In particular, such a grain boundary is portrayed in terms of an array of voids or asymmetric cracks upon whose surfaces are distributed surface dislocations. These surface dislocations are in fact the grain boundary dislocations which satisfy the stress-free boundary conditions on the surface of the grain boundary voids. The energy of a grain boundary is readily obtained in terms of this model. 
 
 
 
Ein nicht-starres Modell einer Knickwand mit beliebiger Fehlorientierung wird formuliert. Insbesondere wird eine derartige Korngrenze mit einer Anordnung von Hohlraumen oder asymmetrischen Rissen gezeichnet, auf deren Oberlache Oberflachenversetzungen verteilt sind. Diese Oberflachenversetzungen sind tatsachlich die Korngrenzenversetzungen, die die spannungsfreien Grenzbedingungen an der Oberflache der Korngrenzenhohlraume befriedigen. Die Energie einer Korngrenze wird mit diesem Modell bequem erhalten.}, number={2}, journal={physica status solidi (a)}, author={Marcinkowski, M.J. and Jagannadham, K.}, year={1978}, pages={601–610} }
 @article{jagannadham_1977, title={Debonding of circular second phase particles}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017629758&partnerID=MN8TOARS}, DOI={10.1016/0013-7944(77)90081-9}, abstractNote={The plastic relaxation of a shear crack situated normal to the interface of a second phase particle of circular cross section is quantitatively analyzed. The ratio of applied stress to yield stress and the relative displacement of crack faces at the tips in the matrix and at the interface of the second phase particle are related to the crack parameters—namely the length of the crack, the width of the plastic zone along the interface and the width of the plastic zone in the matrix. The effect of the shear modulus and size of the second phase particle on the behavior of the plastic zones is determined. A critical value of the relative displacement of the crack faces at the tip is used as the criterion to determine the tendency to brittle extension of the crack into the matrix or along the interface. Conclusions are made on the debonding of the second phase particle from the matrix.}, number={3}, journal={Engineering Fracture Mechanics}, author={Jagannadham, K.}, year={1977}, pages={689–696} }
 @article{sadananda_jagannadham_marcinkowski_1977, title={Discrete dislocation analysis of a plastic tensile crack}, volume={44}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017635195&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210440228}, abstractNote={The behavior of a tensile crack is studied using the discrete dislocation method. The crack behavior is classified into four categories, namely elastic, discontinuous plastic, elasto-plastic, and continuous plastic. It is found that the continuous plastic tensile crack is a more realistic dislocation model of the crack behavior in ductile materials. This crack requires the highest energy to reach the Griffith configuration where the plastic zone is generated on a slip plane inclined at sixty degrees to the crack plane. The relaxation of the crack tip stress field of a shear crack is compared with that of a tensile crack and some important conclusions are arrived at concerning the difference in the behavior of these two types of cracks. 
 
 
 
Mit der Methode diskreter Versetzungen wird das Verhalten des Dehnungsbruches untersucht. Das Bruchverhalten wird in vier Kategorien eingeteilt, elastische, diskontinuierlich plastische, elasto-plastische und kontinuierlich plastische. Es wird gefunden, das der kontinuierlich plastische Dehnungsbruch ein realistischeres Versetzungsmodell des Bruchverhaltens in duktilen Materialien darstellt. Dieser Bruch erfordert die hochste Energie, um die Griffith-Konfiguration zu erreichen, wobei die plastische Zone auf einer Gleitebene erzeugt wird, die sechzig Grad gegen die Bruchebene geneigt ist. Die Relaxation des Spannungsfeldes der Bruchspitze eines Scherbruches wird mit der eines Dehnungsbruches verglichen und einige wesentliche Schlusse uber den Unterschied im Verhalten dieser beiden Brucharten werden gezogen.}, number={2}, journal={physica status solidi (a)}, author={Sadananda, K. and Jagannadham, K. and Marcinkowski, M.J.}, year={1977}, pages={633–642} }
 @article{jagannadham_marcinkowski_1977, title={Dislocation model of the plastic zone at a tensile crack}, volume={42}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017523312&partnerID=MN8TOARS}, DOI={10.1002/pssa.2210420203}, abstractNote={The formation of a plastic zone at the tip of a tensile crack in an infinite homogeneous medium is considered to take place on a slip plane inclined at different angles to the crack plane. A discrete dislocation model is used to represent the crack and the plastic zone. It is found that the inclination of the slip plane to the crack plane depends strongly on the applied stress. Similarly, the critical size of the crack also depends strongly on the applied stress when the slip plane is inclined at different angles to the crack plane. The size of the plastic crack is related to the total elastic strain energy of the crack in an empirical manner. The length to which the plastic zone is spread along the slip plane is found to be a maximum at an inclination of the slip plane to the crack plane near π/3 for all values of applied stress. 
 
 
 
Es wird angenommen, das die Bildung einer plastischen Zone an der Spitze eines Dehnungsrisses in einem unendlichen, homogenen Medium auf einer Gleitebene stattfindet, die mit der Risebene verschiedene Winkel bildet. Das Modell einer diskreten Versetzung wird benutzt, um den Ris und die plastische Zone darzustellen. Es wird gefunden, das die Neigung der Gleitebene zur Risebene stark von der angelegten Spannung abhangt. In ahnlicher Weise hangt die kritische Grose des Risses ebenfalls stark von der aseren Spannung ab, wenn die Gleitebene verschiedene Winkel mit der Risebene bildet. Die Grose des plastischen Risses wird mit der gesamten elastischen Spannungsenergie des Risses empirisch verknupft. Die Lange, mit der die plastische Zone in der Gleitebene ausgebreitet ist, hat ein Maximum bei der Neigung der Gleitebene zur Risebene bei etwa π/3 fur alle Werte der auseren Spannung.}, number={2}, journal={physica status solidi (a)}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1977}, pages={439–447} }
 @article{jagannadham_marcinkowski_1977, title={Loss of coherency across an interface}, volume={48}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017534573&partnerID=MN8TOARS}, DOI={10.1063/1.324297}, abstractNote={The loss of coherency across a two-phase interface was studied by invoking a dislocation model of the two-phase interface. In particular, the interface consists of periodically arranged misfit dislocations with interface dislocations distributed in between the misfit dislocations. A coherent interface consists of uniformly distributed interface dislocations and becomes noncoherent by rearrangement of the interface dislocations. This rearrangement of interface dislocations was studied by the techniques of continuously distributed dislocations and by the method of discrete distributions of dislocations. The atomic step produced across the interface is related to the physical properties of the two phases and to the magnitude of the frictional stress across the interface.}, number={9}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Marcinkowski, M.J.}, year={1977}, pages={3788–3797} }
 @article{jagannadham_1977, title={The attractive and repulsive forces on a lattice screw dislocation}, volume={48}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-36749107880&partnerID=MN8TOARS}, DOI={10.1063/1.323679}, abstractNote={The properties of a lattice screw dislocation in a crystal in the form of a strip or a circular cylinder or an infinite crystal with a circualr hole or in a composite crystal composed of a soft matrix surrounded by a rigid second phase are determined. It is shown that the misfit stress field in the lattice is altered due to the image stress field. Some important conclusions have been arrived at on the image stress field on the dislocation in all the above situations.}, number={2}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={1977}, pages={547–556} }
 @article{jagannadham_1977, title={Two concentric circular arc cracks in anti-plane strain}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017426674&partnerID=MN8TOARS}, DOI={10.1016/0013-7944(77)90064-9}, abstractNote={The behaviour of two concentric circular arc cracks in anti-plane strain has been analyzed by treating them as pile-ups of screw dislocations. The external stress required to extend the shear cracks in a brittle manner has been determined from the analysis.}, number={1}, journal={Engineering Fracture Mechanics}, author={Jagannadham, K.}, year={1977}, pages={211–215} }
 @article{jagannadham_1976, title={Analysis of a BCS model fatigue crack near a free surface}, volume={12}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017006608&partnerID=MN8TOARS}, DOI={10.1007/BF00037915}, number={5}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1976}, pages={685–690} }
 @article{jagannadham_ramachandran_1976, title={Effect of a second phase particle on the rate of growth of fatigue cracks}, volume={12}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016985377&partnerID=MN8TOARS}, DOI={10.1007/BF00034640}, number={4}, journal={International Journal of Fracture}, author={Jagannadham, K. and Ramachandran, E.G.}, year={1976}, pages={543–546} }
 @article{jagannadham_1976, title={Lattice dislocation near a surface}, volume={47}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0017006473&partnerID=MN8TOARS}, DOI={10.1063/1.322445}, abstractNote={The lattice model for a screw dislocation and for an edge dislocation near a surface and parallel to it are obtained. It has been shown that η/d, which is taken as the width of the dislocation for a Peierls-Nabarro dislocation, increases as the edge or the screw dislocation approaches the surface. The properties of the lattice dislocations are derived. The attractive image stress acting on the dislocation is obtained.}, number={10}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={1976}, pages={4401–4403} }
 @article{jagannadham_1976, title={Plastic extension of a shear crack inside a circular inclusion}, volume={12}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016922283&partnerID=MN8TOARS}, DOI={10.1007/BF00036005}, number={1}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1976}, pages={19–26} }
 @article{jagannadham_1975, title={A comparison of brittle and ductile behaviour of cracks inside a circular inclusion}, volume={20}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016555430&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(75)90155-X}, abstractNote={The brittle and ductile behaviour of a shear crack situated at the centre or at the interface inside a circular inclusion is analyzed. The shear crack in antiplane strain mode is treated as a double pile-up of screw dislocations. The plastic relaxation of the shear crack is analyzed by representing the plastic zone by giant screw dislocations. A critical RDC criterion is used to determine the tendency of the shear crack to extend in a brittle manner across the inclusion. Comparison is made on the behaviour of the plastic zone at the tip of both the cracks. Conclusions are made on the fracture behaviour of a circular inclusion situated in an infinite matrix.}, number={C}, journal={Materials Science and Engineering}, author={Jagannadham, K.}, year={1975}, pages={237–242} }
 @article{jagannadham_1975, title={EFFECT OF A LOCKED SCREW DISLOCATION ON A PILE-UP OF SCREW DISLOCATIONS AT A CIRCULAR INCLUSION WITH THE TIP AT THE INTERFACE.}, volume={16}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016494540&partnerID=MN8TOARS}, DOI={10.2320/matertrans1960.16.183}, abstractNote={The effect of a locked dislocation on a pile-up of screw dislocations at a circular inclusion is analyzed using the method of continuously distributed dislocations when the tip of the pile-up is at the interface. The distribution function is used to obtain the number of dislocations in the pile-up, the stress field due to the pile-up in the second phase and the stress field due to the pile-up on the locked dislocation. The results are used to discuss the deformation and fracture behavior of two-phase alloys containing circular second phase particles. (Received June 3, 1974)}, number={4}, journal={Trans Jap Inst Met}, author={Jagannadham, K.}, year={1975}, pages={183–191} }
 @article{jagannadham_1975, title={EFFECT OF A LOCKED SCREW DISLOCATION ON A PILE-UP OF SCREW DISLOCATIONS AT A CIRCULAR INCLUSION WITH THE TIP AWAY FROM THE INTERFACE.}, volume={16}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016494667&partnerID=MN8TOARS}, DOI={10.2320/matertrans1960.16.193}, abstractNote={The effect of a locked screw dislocation on a pile-up of screw dislocations at a circular inclusion is analyzed using the method of continuously distributed dislocations when the tip of the pile-up is away from the interface. The distribution function is used to obtain the number of dislocations per unit length in the pile-up, the stress field due to the pile-up ahead of the tip in the matrix and the stress field due to the pile-up on the locked dislocation. The results are discussed with reference to deformation and fracture behavior of two-phase alloys.}, number={4}, journal={Trans Jap Inst Met}, author={Jagannadham, K.}, year={1975}, pages={193–198} }
 @article{jagannadham_1975, title={Fracture of a circular inclusion in an infinite matrix}, volume={18}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016483046&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(75)90070-1}, abstractNote={The plastic relaxation of a shear crack situated at the interface inside a second phase of circular cross-section is analyzed. The ratio of applied stress to yield stress and the relative displacement of crack faces at the tip of the crack are related to the crack length, width of the plastic zone and the size of the second phase particle. The results are used to discuss the effect of shear modulus of the matrix on the behavior of the plastic zone at the tip of the crack in the second phase. Conclusions on the fracture behavior of a circular second phase particle in an infinite matrix are made.}, number={1}, journal={Materials Science and Engineering}, author={Jagannadham, K.}, year={1975}, pages={37–40} }
 @article{jagannadham_1975, title={Lattice screw dislocation in a finite crystal}, volume={46}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-36749115827&partnerID=MN8TOARS}, DOI={10.1063/1.321559}, abstractNote={The properties of a lattice screw dislocation in a finite crystal in the form of a strip are determined, taking into account the image forces. It is shown that the properties of a screw dislocation in a finite crystal differ markedly from those of a dislocation in an infinite crystal. When the crystal size becomes infinite the results of the present analysis agree with the results of the P-N model.}, number={12}, journal={Journal of Applied Physics}, author={Jagannadham, K.}, year={1975}, pages={5290–5291} }
 @article{jagannadham_1975, title={Lattice screw dislocation in a finite cylindrical crystal}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016482997&partnerID=MN8TOARS}, DOI={10.1016/0036-9748(75)90204-5}, number={3}, journal={Scripta Metallurgica}, author={Jagannadham, K.}, year={1975}, pages={265–270} }
 @article{jagannadham_1975, title={Plastic extension of a shear crack at a circular inclusion}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016506662&partnerID=MN8TOARS}, DOI={10.1016/0020-7683(75)90032-3}, abstractNote={The plastic relaxation of a shear crack situated normal to the interface of a second phase particle of circular cross-section is quantitatively analyzed. The ratio of applied stress to yield stress and the relative displacement of the crack faces at the tips of the crack in the matrix and the interface in the second phase are related to the crack parameters namely the length of the crack, the width of the plastic zone in the matrix and the second phase. The effect of the shear modulus and size of the second phase particle on the behaviour of the plastic zones is determined. A critical value of the relative displacement of the crack faces at the tip of the crack is used as the criterion to determine the tendency to brittle crack extension into the matrix and the second phase.}, number={5}, journal={International Journal of Solids and Structures}, author={Jagannadham, K.}, year={1975}, pages={593–599} }
 @article{jagannadham_1975, title={Plastic relaxation of a shear crack at a circular inclusion}, volume={13}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016533866&partnerID=MN8TOARS}, DOI={10.1016/0020-7225(75)90011-7}, abstractNote={The plastic relaxation of a shear crack situated normal to the interface of a second phase particle of circular cross-section is analyzed using the method of Atkinson and Kay. The ratio of applied stress to yield stress and the relative displacement of the crack faces at the tip of the crack are related to the crack parameters. The results are used to discuss the effect of the shear modulus and size of the circular second phase particle on the behaviour of the plastic zone.}, number={7-8}, journal={International Journal of Engineering Science}, author={Jagannadham, K.}, year={1975}, pages={725–729} }
 @article{jagannadham_1975, title={Plastic relaxation of circular arc cracks in antiplane strain}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016647647&partnerID=MN8TOARS}, DOI={10.1007/BF00033837}, number={6}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1975}, pages={915–924} }
 @article{jagannadham_raghavan_1975, title={The deformation behavior of the matrix near a planar interface in a two-phase medium}, volume={6}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016424402&partnerID=MN8TOARS}, DOI={10.1007/BF02673679}, number={1}, journal={Metallurgical Transactions A}, author={Jagannadham, K. and Raghavan, K.S.}, year={1975}, pages={123–127} }
 @article{jagannadham_1974, title={A screw dislocation near and inside a partially bonded circular inclusion}, volume={4}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016073183&partnerID=MN8TOARS}, DOI={10.1007/BF00045664}, number={2}, journal={Journal of Elasticity}, author={Jagannadham, K.}, year={1974}, pages={155–161} }
 @article{jaganndham_1974, title={Bauschinger loop in a semi-infinite medium}, volume={8}, ISSN={0036-9748}, url={http://dx.doi.org/10.1016/0036-9748(74)90179-3}, DOI={10.1016/0036-9748(74)90179-3}, number={12}, journal={Scripta Metallurgica}, publisher={Elsevier BV}, author={Jaganndham, K.}, year={1974}, month={Dec}, pages={1397–1404} }
 @article{jagannadham_ramachandran_1974, title={Critical misfit for generation of dislocations at second-phase particles}, volume={45}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016068796&partnerID=MN8TOARS}, DOI={10.1063/1.1663606}, abstractNote={The generation of dislocation loops around spherical second-phase particles by various models is examined. A theoretical lower limit to the critical misfit is obtained and it is found to agree with the experimentally observed values.}, number={6}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Ramachandran, E.G.}, year={1974}, pages={2406–2408} }
 @article{jagannadham_raghavan_1974, title={Pile-up of screw dislocations at a circular inclusion}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016072222&partnerID=MN8TOARS}, DOI={10.1007/BF00113929}, number={2}, journal={International Journal of Fracture}, author={Jagannadham, K. and Raghavan, K.S.}, year={1974}, pages={241–249} }
 @article{jagannadham_raghavan_1974, title={Pile-up of screw dislocations inside an inclusion of circular cross section}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250424121&partnerID=MN8TOARS}, DOI={10.1007/BF00955079}, number={1}, journal={International Journal of Fracture}, author={Jagannadham, K. and Raghavan, K.S.}, year={1974}, pages={53–59} }
 @article{jagannadham_1974, title={Pile-ups of screw dislocations in two-phase systems}, volume={8}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016026172&partnerID=MN8TOARS}, DOI={10.1016/0036-9748(74)90462-1}, abstractNote={Pile-ups of screw dislocations in two-phase systems are analyzed using the method of continuously distributed dislocations and the polynomial method. The two-phase systems considered here can broadly be divided into two categories; first, when the second phase is circular in cross-section and second, when the interface is planar between the two phases. The behaviour of shear cracks is investigated by treating them as double pile-ups of screw dislocations. Relationships are established among various parameters connected with the pile-ups and extended towards quantitative criteria for propagation of cracks in two-phase systems. The plastic relaxation of the shear cracks is also investigated and conclusions made on the behaviour of the plastic zone.}, number={2}, journal={Scripta Metallurgica}, author={Jagannadham, K.}, year={1974}, pages={149–152} }
 @article{jagannadham_1974, title={Plastic relaxation of a shear crack at a circular inclusion}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250416093&partnerID=MN8TOARS}, DOI={10.1007/BF00035507}, number={3}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1974}, pages={445–447} }
 @article{jagannadham_1974, title={Plastic relaxation of a shear crack inside a circular inclusion}, volume={10}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250414011&partnerID=MN8TOARS}, DOI={10.1007/BF00035509}, number={3}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1974}, pages={452–454} }
 @article{jagannadham_raghavan_1974, title={Plastic relaxation of an infinite periodic sequence of cracks in a semi-infinite solid}, volume={13}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-49549159589&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(74)90186-4}, number={2}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Raghavan, K.S.}, year={1974}, pages={189–190} }
 @article{jagannadham_raghavan_1974, title={The image effects on a pile-up of screw dislocations near a circular interface}, volume={15}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0016091968&partnerID=MN8TOARS}, DOI={10.1016/0025-5416(74)90058-5}, abstractNote={In order to assess the image effects due to a second phase, a pile-up of screw dislocations situated at a distance from a circular interface is analyzed using the method of continuously distributed dislocations. The results show that the image effects become unimportant only after a distance determined by the relative shear moduli of the two phases and the size of the particle. The interaction of the second phase with the applied stress is more important than that with the pile-up. The results are extended to give a quantitative criterion for crack propagation.}, number={2-3}, journal={Materials Science and Engineering}, author={Jagannadham, K. and Raghavan, K.S.}, year={1974}, pages={247–251} }
 @article{jagannadham_1973, title={A screw dislocation near a partially bonded circular inclusion}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250444218&partnerID=MN8TOARS}, DOI={10.1007/BF00035966}, number={1}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1973}, pages={119–121} }
 @article{jagannadham_1973, title={An edge dislocation near a partially bonded circular inclusion}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-34250429172&partnerID=MN8TOARS}, DOI={10.1007/BF00035963}, number={1}, journal={International Journal of Fracture}, author={Jagannadham, K.}, year={1973}, pages={109–112} }
 @article{jagannadham_raghavan_1973, title={Infinite periodic sequence of relaxed cracks in a semi-infinite solid}, volume={11}, ISSN={0025-5416}, url={http://dx.doi.org/10.1016/0025-5416(73)90088-8}, DOI={10.1016/0025-5416(73)90088-8}, abstractNote={The Bilby-Cottrell-Swinden model is used to analyse the behaviour of an infinite periodic sequence of relaxed cracks at and near a free surface in a semi-infinite solid. The applied stress and the yield stress are related to the crack parameters using the condition for boundedness of the distribution function. The relative displacement of the crack faces at the tip of the cracks is obtained. Les auteurs utilisent le modèle de Bilby, Cottrell et Swinden pour analyser le comportement d'un solide semi-infini contenant une série périodique infinie de fissures relaxées, localisées le long d'une surface libre ou au voisinage de celle-ci. Ils relient la contrainte appliquée et la limite d'élasticité aux paramètres de la fissure, en se servant du fait que la fonction de distribution doit être bornée. Ils obtiennent ainsi l'écartement des lèvres de la fissure en son extrémité. Das Bilby-Cottrell-Swinden-Modell wird für die Analyse des Verhaltens einer unendlichen periodischen Anordnung relaxierter Risse an oder nahe der freien Oberfläche eines Festkörper-Halbraums benützt. Zwischen angelegter Spannung und Flieβspannung einerseits sowie den Riβparametern andererseits wird ein Zusammenhang hergestellt; dazu wird die Bedingung für die Begrenztheit der Verteilungsfunktion benützt. Man gewinnt die relative Verschiebung der Riβflächen an den Riβspitzen.}, number={5}, journal={Materials Science and Engineering}, publisher={Elsevier BV}, author={Jagannadham, K and Raghavan, K.S}, year={1973}, month={May}, pages={242–246} }
 @article{jagannadham_raghavan_1973, title={On the behaviour of a pair of shear cracks near a planar interface}, volume={7}, ISSN={0036-9748}, url={http://dx.doi.org/10.1016/0036-9748(73)90091-4}, DOI={10.1016/0036-9748(73)90091-4}, number={5}, journal={Scripta Metallurgica}, publisher={Elsevier BV}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, month={May}, pages={431–436} }
 @article{jagannadham_raghavan_1973, title={On the mechanism of cross slip in two-phase alloys}, volume={7}, ISSN={0036-9748}, url={http://dx.doi.org/10.1016/0036-9748(73)90173-7}, DOI={10.1016/0036-9748(73)90173-7}, number={1}, journal={Scripta Metallurgica}, publisher={Elsevier BV}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, month={Jan}, pages={21–26} }
 @article{jagannadham_ramachandran_1973, place={Madras, Madras, India); Raghavan, K.S}, title={Pile-up of screw dislocations in a two-phase system}, volume={9}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0015761736&partnerID=MN8TOARS}, DOI={10.1007/BF00036321}, number={4}, journal={International Journal of Fracture}, publisher={Indian Inst. of Technol}, author={Jagannadham, K and Ramachandran, E.G.}, year={1973}, month={Jul}, pages={397–404} }
 @article{jagannadham_raghavan_1973, title={Plastic relaxation of a shear crack near a planar interface}, volume={44}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0015673598&partnerID=MN8TOARS}, DOI={10.1063/1.1661974}, abstractNote={The plastic relaxation of a shear crack near a planar interface of a two-phase system composed of two welded elastic half-planes is considered. Using the models suggested by Bilby, Cottrell, and Swinden, and by Atkinson and Kay, expressions relating the applied stress, the yield stress, and the width of the plastic zone are obtained. The relative displacement of the crack faces is also obtained and the behavior of the plastic zone is discussed.}, number={10}, journal={Journal of Applied Physics}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, pages={4413–4416} }
 @article{jagannadham_raghavan_1973, title={Screw dislocation pile-ups at and near a planar interface of a two-phase system}, volume={11}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0015630103&partnerID=MN8TOARS}, DOI={10.1016/0020-7225(73)90093-1}, abstractNote={The method of continuously distributed dislocations is used in analyzing the behaviour of pile-ups of screw dislocations in two-phase systems. Two types of pile-ups are analyzed, namely, a pile-up of screw dislocations of length ‘L’ situated at a distance ‘a’ from the interface for L/2a <12 and two pile-ups of screw dislocations of length L situated one above the other at a distance of separation h for L/2a <12. The effect of the shear modulus of the second phase and the pile-up parameters on the behaviour of the pile-ups is discussed. Conclusions have been drawn on the fracture behaviour of the two-phase systems. La méthode des dislocations réparties d'une façon continue est utilisée pour analyser le comportement d'accumulations de dislocations de vis dans des systèmes à deux phases. Deux types d'accumulations sont analysés, c'est-à-dire une accumulation de dislocations de vis de longueur ‘L’ situées à une distance ‘a’ de l'interface pour L/2a < 12 et deux accumul ations de dislocations de vis de longueur ‘L’ situées l'une au-desus de l'autre à une distance de séparation h pour L/h < 12. L'effet du module de cisaillement de la seconde phase et des paramètres d'accumulation sur le comportement des accumulations est étudié. Des conclusions ont été tirées sur le comportement de cassure de systèmes à deux phases. Die Methode stetig verteilter Verdrängungen wird verwendet, um das Verhalten von Anhäufungen von Schraubenverdrängungen in Zweiphasensystemen zu analysieren. Es werden zwei Typen von Anhäufungen analysiert, nähmlich eine Anhäufung von Schraubenverdrängungen der Länge ‘L’, in einer Entfernung ‘a’ von der Grenzfläche für L/2a < 12 befindlich, und zwei Anhäufungen von Schraubenver-drängungen der Länge L, übereinander befindlich, mit einem Trennabstand h für L/h < 12. Die Wirkung des Schermoduls der zweiten Phase und der Anhäufungsparameter auf das Verhalten der Anhäufungen wird besprochen. Es wurden Schlüsse auf das Bruchverhalten des Zweiphasensystems gezogen. Nell'analisi del comportamento di ammucchiamenti di spostamenti di vite in sistemi a due stadi si usa il metodo degli spostamenti continuamente distribuiti. Si analizzano due tipi di ammucchiamenti, e precisamente un ammuechiamento degli spostamenti di vite di lunghezza ‘L’ a una distanza ‘a’ dall'interfaccia per L/h < 12 e due ammucchiamenti di spostamenti di vite di lunghezza ‘L’ uno sopra l'altro a una distanza di separazione h per L/h < 12. L'effetto del modulo di taglio del seconde stadio e i parametri d'ammuechiamento sul comportamento degli ammucchiamenti sono oggetto di discussione. L'A. Tira conclusioni sul comportamento alla frattura dei sistemi a due stadi. Пa ocнoвe мeтoдa нeпpepывныч pacпpeдeлeниыч диcлoкaций дaн aнaлиз пoвeдeния нaкoплeний виитoвыч диcлoкaций в двyчфaзныч cиcтeмaч. aиaлизиpoвaиы нaкoплeния двyч типoв: oднoe иaкoплeниe винтoвыч диcлoкaций длины ⪡ L ⪢, нaчoдящeecь в pacтoянии ⪡ a ⪢ oт пoвepчнocти paздeлa пpи L/h < 12,двa нaкoплeния винтoвыч диcлoкaций длины L, нaчoдящиecя oднaя нaд дpyгoй в pacтoянии paздeлeния h пpи L/h < 12.oбcyждeнo влияниe мoдyля cдвигa втopoй фaзы и пapaмeтpoв нaкoплeния нa пoвeдeниe нaкoплeний. cдeлaны вывoды o явлeнии излoмa в cлyчae двyчфaзныч cиcтeм.}, number={5}, journal={International Journal of Engineering Science}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, pages={501–517} }
 @article{jagannadham_raghavan_1973, title={Stacked screw dislocation arrays in an anisotropic two-phase medium}, volume={4}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-51649180156&partnerID=MN8TOARS}, DOI={10.1007/BF02645623}, number={4}, journal={Metallurgical Transactions}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, pages={1171–1172} }
 @article{jagannadham_raghavan_1973, title={The effect of a locked screw dislocation on a pile-up of screw dislocations in a two phase system}, volume={4}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0015681646&partnerID=MN8TOARS}, DOI={10.1007/BF02644263}, number={11}, journal={Metallurgical Transactions}, author={Jagannadham, K. and Raghavan, K.S.}, year={1973}, pages={2599–2604} }
 @article{jagannadham_raghavan_1972, place={Madras, Madras, India); Raghavan}, title={On the behaviour of shear cracks outside a circular inclusion}, volume={8}, number={4}, journal={International Journal of Fracture Mechanics}, publisher={Indian Inst. of Technol}, author={Jagannadham, K and Raghavan, K. S.}, editor={Raghavan, K. S.Editor}, year={1972}, month={Dec}, pages={462–464} }
 @article{jagannadham_raghavan_1972, title={The behaviour of shear cracks inside a circular inclusion}, volume={8}, ISSN={0020-7268 1573-2673}, url={http://dx.doi.org/10.1007/bf00191110}, DOI={10.1007/bf00191110}, number={4}, journal={International Journal of Fracture Mechanics}, publisher={Springer Science and Business Media LLC}, author={Jagannadham, K. and Raghavan, K.S.}, year={1972}, month={Dec} }