@article{chen_zhou_zhu_li_zhang_narayan_wang_jia_2016, title={Stabilizing new bismuth compounds in thin film form}, volume={31}, ISSN={["2044-5326"]}, DOI={10.1557/jmr.2016.391}, abstractNote={Abstract}, number={22}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Chen, Aiping and Zhou, Honghui and Zhu, Yuanyuan and Li, Leigang and Zhang, Wenrui and Narayan, Jagdish and Wang, Haiyan and Jia, Quanxi}, year={2016}, month={Nov}, pages={3530–3537} }
 @article{zhang_li_chen_li_zhu_xia_lu_boullay_wu_zhu_et al._2016, title={Two-Dimensional Layered Oxide Structures Tailored by Self Assembled Layer Stacking via Interfacial Strain}, volume={8}, ISSN={["1944-8252"]}, DOI={10.1021/acsami.6b03773}, abstractNote={Study of layered complex oxides emerge as one of leading topics in fundamental materials science because of the strong interplay among intrinsic charge, spin, orbital, and lattice. As a fundamental basis of heteroepitaxial thin film growth, interfacial strain can be used to design materials that exhibit new phenomena beyond their conventional forms. Here, we report a strain-driven self-assembly of bismuth-based supercell (SC) with a two-dimensional (2D) layered structure. With combined experimental analysis and first-principles calculations, we investigated the full SC structure and elucidated the fundamental growth mechanism achieved by the strain-enabled self-assembled atomic layer stacking. The unique SC structure exhibits room-temperature ferroelectricity, enhanced magnetic responses, and a distinct optical bandgap from the conventional double perovskite structure. This study reveals the important role of interfacial strain modulation and atomic rearrangement in self-assembling a layered singe-phase multiferroic thin film, which opens up a promising avenue in the search for and design of novel 2D layered complex oxides with enormous promise.}, number={26}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Zhang, Wenrui and Li, Mingtao and Chen, Aiping and Li, Leigang and Zhu, Yuanyuan and Xia, Zhenhai and Lu, Ping and Boullay, Philippe and Wu, Lijun and Zhu, Yimei and et al.}, year={2016}, month={Jul}, pages={16845–16851} }
 @article{ma_xu_zhou_moering_narayan_zhu_2015, title={Alloying effect on grain-size dependent deformation twinning in nanocrystalline Cu-Zn alloys}, volume={95}, ISSN={["1478-6443"]}, DOI={10.1080/14786435.2014.1000418}, abstractNote={Grain-size dependency of deformation twinning has been previously reported in nanocrystalline face-centred-cubic metals, which results in an optimum grain-size range for twin formation. Here, we report, for the first time in experiments, the observed optimum grain sizes for deformation twins in nanocrystalline Cu–Zn alloys which slightly increase with increasing Zn content. This result agrees with the reported trend but is much weaker than predicted by stacking-fault-energy based models. Our results indicate that alloying changes the relationship between the stacking-fault and twin-fault energy and therefore affects the optimum grain size for deformation twinning. These observations should be also applicable to other alloy systems.}, number={3}, journal={PHILOSOPHICAL MAGAZINE}, author={Ma, X. L. and Xu, W. Z. and Zhou, H. and Moering, J. A. and Narayan, J. and Zhu, Y. T.}, year={2015}, month={Jan}, pages={301–310} }
 @article{zhou_xu_jian_cheng_ma_guo_mathaudhu_wang_zhu_2014, title={A new metastable precipitate phase in Mg-Gd-Y-Zr alloy}, volume={94}, ISSN={["1478-6443"]}, DOI={10.1080/14786435.2014.913115}, abstractNote={Mg–RE alloys are among the strongest Mg-based alloys due to their unique precipitation structures. A previously unobserved metastable phase (βT) is found to coexist with reported β″ and β′ metastable phases under peak ageing conditions in a Mg–Gd–Y–Zr alloy. The position of the RE elements within the βT phase is identified using atomic-resolution high-angle annular dark field scanning transmission electron microscopy imaging, and the βT phase is shown to have an orthorhombic structure with a stoichiometry of Mg5RE. Based on these observations, a new precipitation sequence is proposed.}, number={21}, journal={PHILOSOPHICAL MAGAZINE}, author={Zhou, H. and Xu, W. Z. and Jian, W. W. and Cheng, G. M. and Ma, X. L. and Guo, W. and Mathaudhu, S. N. and Wang, Q. D. and Zhu, Y. T.}, year={2014}, pages={2403–2409} }
 @misc{zhou_chisholm_gupta_pennycook_narayan_2014, title={Two-dimensional metamaterials for epitaxial heterostructures}, volume={18}, ISSN={["1879-0348"]}, DOI={10.1016/j.cossms.2014.01.001}, abstractNote={We review the use of two-dimensional psuedomorphic materials to accommodate an extraordinary range of misfit and allow novel new phases to be grown epitaxially. These materials assume the structure of the substrate and can thus be regarded as metamaterials. We illustrate these principles through a number of systems, including a detailed structural and spectroscopic study of epitaxial VO2/NiO heterostructures. In this case the metamaterial is VO1+x which is structurally and electronically distinct from the bulk of the VO2 film. In the transition region the crystal structure adopts that of the NiO layer, while the oxidation state of vanadium increases from ∼3+ to ∼4+ with thickness, accompanied by increasing lattice disorder. The formation and evolution of this interfacial phase, VO1+x, accommodates the change in crystal symmetry across the interface from the rock-salt structure of NiO to the rutile structure of VO2. The use of two-dimensional metamaterials opens a wealth of new opportunities for the growth of new materials with novel properties.}, number={1}, journal={CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE}, author={Zhou, H. and Chisholm, M. F. and Gupta, A. and Pennycook, S. J. and Narayan, J.}, year={2014}, month={Feb}, pages={46–52} }
 @article{chen_zhou_bi_zhu_luo_bayraktaroglu_phillips_choi_macmanus-driscoll_pennycook_et al._2013, title={A New Class of Room-Temperature Multiferroic Thin Films with Bismuth-Based Supercell Structure}, volume={25}, ISSN={["0935-9648"]}, DOI={10.1002/adma.201203051}, abstractNote={Intergrowth of two partially miscible phases of BiFeO(3) and BiMnO(3) gives a new class of room-temperature multiferroic phase, Bi(3) Fe(2) Mn(2) O(10+δ) , which has a unique supercell (SC) structure. The SC heterostructures exhibit simultaneously room-temperature ferrimagnetism and remanent polarization. These results open up a new avenue for exploring room-temperature single-phase multiferroic thin films by controlling the phase mixing of two perovskite BiRO(3) (R = Cr, Mn, Fe, Co, Ni) materials.}, number={7}, journal={ADVANCED MATERIALS}, author={Chen, Aiping and Zhou, Honghui and Bi, Zhenxing and Zhu, Yuanyuan and Luo, Zhiping and Bayraktaroglu, Adrian and Phillips, Jamie and Choi, Eun-Mi and MacManus-Driscoll, Judith L. and Pennycook, Stephen J. and et al.}, year={2013}, month={Feb}, pages={1028–1032} }
 @article{pennycook_zhou_chisholm_borisevich_varela_gazquez_pennycook_narayan_2013, title={Misfit accommodation in oxide thin film heterostructures}, volume={61}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2012.09.069}, abstractNote={Complex oxides are of intense interest due to their diverse properties, such as colossal magnetoresistance and superconductivity. Their complexity arises not only from the number of constituent elements, but also from their tolerance of non-stoichiometry and the structural complexity of these perovskite-based materials, e.g. the distortions and rotations of the oxygen octahedra surrounding the B-site cation. For these reasons, misfit accommodation in these materials is far more complex than in simpler materials, and can involve several different mechanisms simultaneously. In some cases, interfaces can be free from any misfit dislocations, lattice mismatch being accommodated via incorporation of oxygen vacancies, which take an ordered periodic arrangement. Interfaces may also present a perturbation to the octahedral rotations that can dramatically affect properties, not just close to the interface but through the entire film. In oxygen ion conducting materials, the oxygen sublattice may even melt in some situations.}, number={8}, journal={ACTA MATERIALIA}, author={Pennycook, S. J. and Zhou, H. and Chisholm, M. F. and Borisevich, A. Y. and Varela, M. and Gazquez, J. and Pennycook, T. J. and Narayan, J.}, year={2013}, month={May}, pages={2725–2733} }
 @article{zhu_chen_zhou_zhang_narayan_macmanus-driscoll_jia_wang_2013, title={Research Updates: Epitaxial strain relaxation and associated interfacial reconstructions: The driving force for creating new structures with integrated functionality}, volume={1}, number={5}, journal={APL Materials}, author={Zhu, Y. Y. and Chen, A. P. and Zhou, H. H. and Zhang, W. R. and Narayan, J. and MacManus-Driscoll, J. L. and Jia, Q. X. and Wang, H. Y.}, year={2013} }
 @article{zhou_chisholm_pant_chang_gazquez_pennycook_narayan_2010, title={Atomic structure of misfit dislocations in nonpolar ZnO/Al2O3 heterostructures}, volume={97}, number={12}, journal={Applied Physics Letters}, author={Zhou, H. and Chisholm, M. F. and Pant, P. and Chang, H. J. and Gazquez, J. and Pennycook, S. J. and Narayan, J.}, year={2010} }
 @article{yang_nori_zhou_narayan_2009, title={Defect-mediated room temperature ferromagnetism in vanadium dioxide thin films}, volume={95}, number={10}, journal={Applied Physics Letters}, author={Yang, T. H. and Nori, S. and Zhou, H. H. and Narayan, J.}, year={2009} }
 @article{zhou_maiorov_baily_dowden_kennison_stan_holesinger_jia_foltyn_civale_2009, title={Thickness dependence of critical current density in YBa2Cu3O7-delta films with BaZrO3 and Y2O3 addition}, volume={22}, number={8}, journal={Superconductor Science & Technology}, author={Zhou, H. and Maiorov, B. and Baily, S. A. and Dowden, P. C. and Kennison, J. A. and Stan, L. and Holesinger, T. G. and Jia, Q. X. and Foltyn, S. R. and Civale, L.}, year={2009} }
 @article{jin_zhou_graham_narayan_2007, title={In situ Raman spectroscopy of annealed diamondlike carbon–metal composite films}, volume={253}, ISSN={0169-4332}, url={http://dx.doi.org/10.1016/j.apsusc.2007.01.022}, DOI={10.1016/j.apsusc.2007.01.022}, abstractNote={Diamondlike carbon films and diamondlike carbon–metal composite films may provide increased component reliability, decreased fuel consumption, decreased noise/vibration/harshness (NVH), and decreased lubricant use in next generation automotive components. Raman spectra were obtained for diamondlike carbon, diamondlike carbon–platinum composite films, and diamondlike carbon–gold composite films, which were annealed to a temperature of 523 °C. The Raman spectra for these films were fitted using a two-Gaussian function. The variation of the G-peak position, the D-peak position, and the ID/IG ratio was examined as a function of temperature. The unalloyed diamondlike carbon film demonstrated greater thermal stability than the diamondlike carbon–noble metal composite films. These results suggest that the operating temperatures of the diamondlike carbon-coated automotive components must be kept under careful consideration.}, number={15}, journal={Applied Surface Science}, publisher={Elsevier BV}, author={Jin, C. and Zhou, H. and Graham, S. and Narayan, R.J.}, year={2007}, month={May}, pages={6487–6492} }
 @article{jin_zhou_wei_narayan_2006, title={Three-dimensional self-organization of crystalline gold nanoparticles in amorphous alumina}, volume={89}, DOI={10.1063/1.2422910}, abstractNote={Multilayered heterostructures containing gold nanoparticles embedded in amorphous alumina matrices were deposited on silicon (001) substrates using pulsed laser deposition. The three-dimensional ordering of gold nanoparticles within these multilayered heterostructures was investigated using cross-sectional transmission electron microscopy and image Fourier transformation. Self-organization of gold nanoparticles along the vertical direction was observed in films grown at 20 and at 320°C. Self-organization occurred by means of two different growth modes; both vertically correlated growth (top-on-top) and anticorrelated growth (top-on-middle) mechanisms were observed. The results of these studies suggest that the driving force for vertical ordering in this material is related to the long-range elastic interactions among the nanoparticles within the growing films.}, number={26}, journal={Applied Physics Letters}, author={Jin, C. M. and Zhou, H. H. and Wei, W. and Narayan, R.}, year={2006} }
 @article{jin_narayan_tiwari_zhou_kvit_narayan_2005, title={Epitaxial growth of zinc oxide thin films on silicon}, volume={117}, ISSN={0921-5107}, url={http://dx.doi.org/10.1016/j.mseb.2004.12.003}, DOI={10.1016/j.mseb.2004.12.003}, abstractNote={Epitaxial zinc oxide thin films were grown on Si(1 1 1) using aluminum nitride and magnesium oxide/titanium nitride buffer layers. The resultant films were examined using transmission electron microscopy, X-ray diffraction, electrical conductivity, and photoluminescence spectroscopy. The following epitaxial relationships were observed in the ZnO/AlN/Si(1 1 1) heterostructure: ZnO[0 0 0 1] || AlN[0 0 0 1] || Si[1 1 1] along the growth direction, and ZnO[21¯1¯0] || AlN[21¯1¯0] || Si[011¯] along the in-plane direction. Domain-matching epitaxial growth of TiN on Si(1 1 1) substrate allows successful epitaxial growth of MgO and ZnO layers in a ZnO/MgO/TiN/Si(1 1 1) heterostructure. The epitaxial relationships observed for this heterostructure were ZnO[0 0 0 1] || MgO/TiN/Si[1 1 1] along the growth direction and ZnO[21¯1¯0] || MgO/TiN/Si[011¯] along in-plane direction. The resultant ZnO films demonstrate excellent electrical and optical properties. ZnO thin films exhibit extremely bright ultraviolet luminescence with relatively weak green-band emission.}, number={3}, journal={Materials Science and Engineering: B}, publisher={Elsevier BV}, author={Jin, Chunming and Narayan, Roger and Tiwari, Ashutosh and Zhou, Honghui and Kvit, Alex and Narayan, Jagdish}, year={2005}, month={Mar}, pages={348–354} }
 @article{kumar_yarmolenko_sarkar_narayan_zhou_tiwari_2004, title={Pulsed laser deposition assisted novel synthesis of self-assembled magnetic nanoparticles}, volume={35}, ISSN={["1359-8368"]}, DOI={10.1016/j.compositesb.2003.08.002}, abstractNote={We report here a novel thin film processing method based upon pulsed laser deposition to process nanocrystalline materials with accurate size and interface control with improved magnetic properties. Using this method, single-domain nanocrystalline Fe and Ni particles in the 5–10 nm size range embedded in amorphous alumina as well as in crystalline TiN have been produced. By controlling the size distribution in confined layers, it was possible to tune the magnetic properties from superparamagnetic to ferromagnetic behavior. Magnetic hysteresis characteristics below the blocking temperature are consistent with single-domain behavior. The paper also presents our results from investigations in which scanning transmission electron microscopy with atomic number contrast (STEM-Z) and electron energy loss spectroscopy (EELS) were used to understand the atomic structure of Ni nanoparticles and interface between the nanoparticles and the surrounding matrices. It was interesting to learn from EELS measurements at interfaces of individual grains that Ni in alumina matrix does not form an ionic bond indicating the absence of metal–oxygen bond at the interface. The absence of metal–oxygen bond, in turn, suggests the absence of any dead layer on Ni nanoparticles even in an oxide matrix.}, number={2}, journal={COMPOSITES PART B-ENGINEERING}, author={Kumar, D and Yarmolenko, S and Sarkar, J and Narayan, J and Zhou, H and Tiwari, A}, year={2004}, pages={149–155} }
 @article{zhou_kumar_kvit_tiwari_narayan_2003, title={Formation of self-assembled epitaxial nickel nanostructures}, volume={94}, ISSN={["1089-7550"]}, DOI={10.1063/1.1609046}, abstractNote={Highly orientated nickel magnetic nanoparticles were obtained by pulsed laser deposition technique on silicon (100) substrate using epitaxial titanium nitride film as the template. These nanoparticles have been characterized by conventional and high-resolution transmission electron microscopy, scanning transmission electron microscopy Z-contrast imaging, and x-ray diffraction techniques. The results have shown that the growth of nickel on epitaxially grown titanium nitride follows a three-dimensional island growth mechanism. The predominant orientation of nickel islands observed is Ni(100)∥TiN(100)∥Si(100), the so-called “cube-on-cube” orientation relation. The islands are faceted with a truncated pyramidal shape and bounded by (111) planes at sides and (100) plane at the top. Islands with nontruncated pyramidal shape were also found in some samples, but with rotational orientation relations, where the nickel crystal rotates with an approximate angle of 90° with respect to one of TiN 〈110〉 directions parallel to the interface. The appearance of this rotational epitaxial growth did not show any obvious deposition temperature dependence in the range of 400–650 °C, rather it seemed to be closely related to the crystalline quality of TiN template. The actual size of islands varies from a few nanometers to tens of nanometers, depending on the deposition time and temperature. The three-dimensional growth of nickel islands and the island faceting could be explained by the surface energy anisotropy of both nickel and titanium nitride.}, number={8}, journal={JOURNAL OF APPLIED PHYSICS}, author={Zhou, H and Kumar, D and Kvit, A and Tiwari, A and Narayan, J}, year={2003}, month={Oct}, pages={4841–4846} }
 @article{kumar_zhou_nath_kvit_narayan_craciun_singh_2002, title={Improved magnetic properties of self-assembled epitaxial nickel nanocrystallites in thin-film ceramic matrix}, volume={17}, ISSN={["0884-2914"]}, DOI={10.1557/JMR.2002.0107}, abstractNote={Nanocrystalline nickel particles were embedded in amorphous alumina and crystalline TiN matrices using a pulsed laser deposition process to investigate the effect of texturing on magnetic properties of nickel nanocrystallites. The crystalline quality of both the matrix and magnetic particles was investigated by cross-sectional high-resolution transmission electron microscopy. The embedded Ni nanocrystals were found to be epitaxial in the case of the TiN matrix and polycrystalline in Al2O3 amorphous matrix. The Ni nanocrystals on TiN/Si grow epitaxially because the TiN acting as a template grows epitaxially on Si substrate via domain epitaxy. On the other hand, Ni nanocrystals in the Al2O3 matrix are polycrystalline because of the amorphous nature of the alumina matrix. Magnetization versus temperature measurements have shown that the blocking temperature, above which the samples lose magnetization–field (M–H) hysteretic behavior, of the Ni–TiN sample (approximately 190 K) is significantly higher than that of Ni–Al2O3 sample (approximately 30 K) with a similar size distribution of embedded magnetic particles. A comparison of the values of coercivity (Hc) of the two samples, measured from M–H data, indicates that epitaxial Ni nanocrystals also exhibit significantly higher coercivity than polycrystalline Ni particles in amorphous alumina matrix. The high values of TB and Hc of Ni–TiN samples with respect to TB of N–A12O3 samples are believed to be associated with preferred alignment of nanocrystallites.}, number={4}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Kumar, D and Zhou, H and Nath, TK and Kvit, AV and Narayan, J and Craciun, V and Singh, RK}, year={2002}, month={Apr}, pages={738–742} }