@article{negi_kim_hua_timofeeva_zhang_zhu_peters_kumah_jiang_liu_2023, title={Ferroelectric Domain Wall Engineering Enables Thermal Modulation in PMN-PT Single Crystals}, volume={4}, ISSN={["1521-4095"]}, url={https://doi.org/10.1002/adma.202211286}, DOI={10.1002/adma.202211286}, abstractNote={Abstract}, journal={ADVANCED MATERIALS}, author={Negi, Ankit and Kim, Hwang Pill and Hua, Zilong and Timofeeva, Anastasia and Zhang, Xuanyi and Zhu, Yong and Peters, Kara and Kumah, Divine and Jiang, Xiaoning and Liu, Jun}, year={2023}, month={Apr} }
 @article{yang_zhang_reynolds_kumah_xu_2023, title={The Role of Carbon Content: A Comparison of the Nickel Particle Size and Magnetic Property of Nickel/Polysiloxane-Derived Silicon Oxycarbide}, volume={1}, ISSN={["1527-2648"]}, url={https://doi.org/10.1002/adem.202201453}, DOI={10.1002/adem.202201453}, abstractNote={A facile and novel processable method to synthesize the Ni nanoparticles (Ni NPs) by tailoring their size in the matrix of the silicon oxycarbide (SiOC) ceramic system is reported. This method is based on polymer‐derived ceramics (PDCs), instead of the conventional powder route. The specific structural characteristics and magnetic properties of the various Ni NPs/SiOC composites as a function of carbon content are systematically investigated. The magnetic properties are experimentally investigated as a function of NP size and measurement temperature. It is demonstrated that the change in the size of Ni NPs (average from ≈4 to ≈ 19 nm) determines the magnetic nature of superparamagnetism. Zero‐field‐cooled (ZFC) and field‐cooled (FC) magnetization studies under magnetic fields of 100 Oe are performed. The saturated M versus H (M–H) loops (saturation magnetization) increase and the coercivity decreases with the size reduction of Ni NPs. It is an indicator of the presence of superparamagnetic behavior and single‐domain NP for ceramic materials.}, journal={ADVANCED ENGINEERING MATERIALS}, author={Yang, Ni and Zhang, Xuanyi and Reynolds, Lewis and Kumah, Divine and Xu, Chengying}, year={2023}, month={Jan} }
 @article{negi_rodriguez_zhang_comstock_yang_sun_jiang_kumah_hu_liu_2023, title={Thickness-Dependent Thermal Conductivity and Phonon Mean Free Path Distribution in Single-Crystalline Barium Titanate}, volume={4}, ISSN={["2198-3844"]}, url={https://doi.org/10.1002/advs.202301273}, DOI={10.1002/advs.202301273}, abstractNote={Abstract}, journal={ADVANCED SCIENCE}, author={Negi, Ankit and Rodriguez, Alejandro and Zhang, Xuanyi and Comstock, Andrew H. H. and Yang, Cong and Sun, Dali and Jiang, Xiaoning and Kumah, Divine and Hu, Ming and Liu, Jun}, year={2023}, month={Apr} }
 @article{ozbek_brooks_zhang_al-tawhid_stoica_zhang_kumah_2022, title={Superconducting phase of TixOy thin films grown by molecular beam epitaxy}, volume={6}, ISSN={["2475-9953"]}, url={https://doi.org/10.1103/PhysRevMaterials.6.064805}, DOI={10.1103/PhysRevMaterials.6.064805}, abstractNote={We investigate the complex relationship between the growth conditions and the structural and transport properties of ${\mathrm{Ti}}_{x}{\mathrm{O}}_{y}$ thin films grown by molecular beam epitaxy. Transport properties ranging from metallicity to superconductivity and insulating states are stabilized by effectively tuning the O/Ti ratio via the Ti flux rate and the O partial pressure ${P}_{\mathrm{O}x}$ for films grown on $(0001)\text{\ensuremath{-}}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ substrates at ${850}^{\ensuremath{\circ}}$ C. A cubic $c\text{\ensuremath{-}}{\mathrm{TiO}}_{1\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta}}$ buffer layer is formed for low O/Ti ratios, while a corundum $\mathrm{cr}\text{\ensuremath{-}}{\mathrm{Ti}}_{2}{\mathrm{O}}_{3}$ layer is formed under higher-oxidizing conditions. Metallicity is observed for $c\text{\ensuremath{-}}{\mathrm{TiO}}_{1\ensuremath{-}\ensuremath{\delta}}$ buffer layers. The superconducting $\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Ti}}_{3}{\mathrm{O}}_{5}$ Magn\'eli phase is found to nucleate on a $c\text{\ensuremath{-}}{\mathrm{TiO}}_{1\ensuremath{-}\ensuremath{\delta}}$ buffer for intermediate ${P}_{\mathrm{O}x}$ conditions, and an insulator-superconducting transition is observed at 4.5 K $({\mathrm{T}}_{C}^{\mathrm{onset}}=6K)$ for 85 nm thick films. Strain relaxation of $\ensuremath{\gamma}\text{\ensuremath{-}}{\mathrm{Ti}}_{3}{\mathrm{O}}_{5}$ occurs with increasing film thickness and correlates with a thickness-dependent increase in ${T}_{C}$ observed for ${\mathrm{Ti}}_{x}{\mathrm{O}}_{y}$ thin films.}, number={6}, journal={PHYSICAL REVIEW MATERIALS}, author={Ozbek, Yasemin and Brooks, Cooper and Zhang, Xuanyi and Al-Tawhid, Athby and Stoica, Vladmir A. and Zhang, Zhan and Kumah, Divine P.}, year={2022}, month={Jun} }
 @article{zhang_penn_wysocki_zhang_loosdrecht_kornblum_lebeau_lindfors-vrejoiu_kumah_2022, title={Thickness and temperature dependence of the atomic-scale structure of SrRuO3 thin films}, volume={10}, ISSN={["2166-532X"]}, url={https://doi.org/10.1063/5.0087791}, DOI={10.1063/5.0087791}, abstractNote={The temperature-dependent layer-resolved structure of 3 to 44 unit cell thick SrRuO3 (SRO) films grown on Nb-doped SrTiO3 substrates is investigated using a combination of high-resolution synchrotron x-ray diffraction and high-resolution electron microscopy to understand the role that structural distortions play in suppressing ferromagnetism in ultra-thin SRO films. The oxygen octahedral tilts and rotations and Sr displacements characteristic of the bulk orthorhombic phase are found to be strongly dependent on temperature, the film thickness, and the distance away from the film–substrate interface. For thicknesses, t, above the critical thickness for ferromagnetism (t > 3 uc), the orthorhombic distortions decrease with increasing temperature above TC. Below TC, the structure of the films remains constant due to the magneto-structural coupling observed in bulk SRO. The orthorhombic distortions are found to be suppressed in the 2–3 interfacial layers due to structural coupling with the SrTiO3 substrate and correlate with the critical thickness for ferromagnetism in uncapped SRO films.}, number={5}, journal={APL MATERIALS}, author={Zhang, Xuanyi and Penn, Aubrey N. and Wysocki, Lena and Zhang, Zhan and Loosdrecht, Paul H. M. and Kornblum, Lior and LeBeau, James M. and Lindfors-Vrejoiu, Ionela and Kumah, Divine P.}, year={2022}, month={May} }