@article{cheng_miao_qin_li_xu_haftbaradaran_dickey_gao_zhu_2015, title={Large anelasticity and associated energy dissipation in single-crystalline nanowires}, volume={10}, ISSN={1748-3387 1748-3395}, url={http://dx.doi.org/10.1038/NNANO.2015.135}, DOI={10.1038/nnano.2015.135}, abstractNote={Anelastic materials exhibit gradual full recovery of deformation once a load is removed, leading to dissipation of internal mechanical energy. As a consequence, anelastic materials are being investigated for mechanical damping applications. At the macroscopic scale, however, anelasticity is usually very small or negligible, especially in single-crystalline materials. Here, we show that single-crystalline ZnO and p-doped Si nanowires can exhibit anelastic behaviour that is up to four orders of magnitude larger than the largest anelasticity observed in bulk materials, with a timescale on the order of minutes. In situ scanning electron microscope tests of individual nanowires showed that, on removal of the bending load and instantaneous recovery of the elastic strain, a substantial portion of the total strain gradually recovers with time. We attribute this large anelasticity to stress-gradient-induced migration of point defects, as supported by electron energy loss spectroscopy measurements and also by the fact that no anelastic behaviour could be observed under tension. We model this behaviour through a theoretical framework by point defect diffusion under a high strain gradient and short diffusion distance, expanding the classic Gorsky theory. Finally, we show that ZnO single-crystalline nanowires exhibit a high damping merit index, suggesting that crystalline nanowires with point defects are promising materials for energy damping applications.}, number={8}, journal={Nature Nanotechnology}, publisher={Springer Science and Business Media LLC}, author={Cheng, Guangming and Miao, Chunyang and Qin, Qingquan and Li, Jing and Xu, Feng and Haftbaradaran, Hamed and Dickey, Elizabeth C. and Gao, Huajian and Zhu, Yong}, year={2015}, month={Jul}, pages={687–691} }
 @article{harris_burch_li_dickey_maria_2015, title={Low‐Temperature Control of Twins and Abnormal Grain Growth in BaTiO
            3}, volume={98}, ISSN={0002-7820 1551-2916}, url={http://dx.doi.org/10.1111/jace.13643}, DOI={10.1111/jace.13643}, abstractNote={The microstructure of polycrystalline barium titanate (BaTiO3) thin films processed with a liquid‐phase can be controlled by the crystallographic orientation of the underlying sapphire substrate. During postdeposition crystallization, the tendency for {111} twin nucleation, which drives subsequent abnormal grain growth, depends upon the specific sapphire facet. Specifically, tilting away from the close‐packed c‐plane modifies the orientation, morphology, and relative amount of an interfacial BaAl2O4 second phase. These factors control the density of twin formation, and thus overall grain size of the crystallized BaTiO3. As the substrate orientation transitions from c‐plane, to r‐plane, to a‐plane, the twin density is reduced, the average grain size decreases systematically from 270 to 130 nm, and the grain structure becomes overall more homogeneous. This twinning mechanism and abnormal grain growth occur by 900°C, several hundred degrees lower than reported previously.}, number={8}, journal={Journal of the American Ceramic Society}, publisher={Wiley}, author={Harris, David T. and Burch, Matthew J. and Li, Jing and Dickey, Elizabeth C. and Maria, Jon‐Paul}, editor={Viehland, D.Editor}, year={2015}, month={May}, pages={2381–2387} }
 @article{hu_li_darling_wang_vanleeuwen_liu_kecskes_dickey_liu_2015, title={Nano-sized Superlattice Clusters Created by Oxygen Ordering in Mechanically Alloyed Fe Alloys}, volume={5}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/srep11772}, DOI={10.1038/srep11772}, abstractNote={Abstract}, number={1}, journal={Scientific Reports}, publisher={Springer Science and Business Media LLC}, author={Hu, Yong-Jie and Li, Jing and Darling, Kristopher A. and Wang, William Y. and VanLeeuwen, Brian K. and Liu, Xuan L. and Kecskes, Laszlo J. and Dickey, Elizabeth C. and Liu, Zi-Kui}, year={2015}, month={Jul} }
 @article{burch_li_harris_maria_dickey_2014, title={Mechanisms for microstructure enhancement in flux-assisted growth of barium titanate on sapphire}, volume={29}, ISSN={0884-2914 2044-5326}, url={http://dx.doi.org/10.1557/jmr.2014.59}, DOI={10.1557/jmr.2014.59}, abstractNote={Abstract}, number={7}, journal={Journal of Materials Research}, publisher={Cambridge University Press (CUP)}, author={Burch, Matthew J. and Li, Jing and Harris, David T. and Maria, Jon-Paul and Dickey, Elizabeth C.}, year={2014}, month={Mar}, pages={843–848} }
 @article{harris_lam_burch_li_rogers_dickey_maria_2014, title={Ultra-high tunability in polycrystalline Ba1−xSrxTiO3 thin films}, volume={105}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4893615}, DOI={10.1063/1.4893615}, abstractNote={Ba0.7Sr0.3TiO3 thin polycrystalline films with an ultra-high capacitance tunability approaching 5:1 at 175 kV/cm were made possible by a flux-assisted synthesis approach. In this process, a small volume fraction of a low melting temperature glass is added during low-temperature sputter deposition. Subsequent annealing activates the liquid phase, which in turn provides the mass transport needed to approach full density, to increase grain size, and to improve crystallinity, and, in so doing, achieves a stronger non-linear dielectric response. Ba0.7Sr0.3TiO3 films with 0%, 1%, 4%, and 7% BaO-3B2O3 flux exhibited grain sizes of 25 nm, 28 nm, 48 nm, and 56 nm, and dielectric tunabilities of 25%, 33%, 64%, and 80% respectively. These values represent substantial improvements when compared to conventionally processed tunable dielectric films.}, number={7}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Harris, D. T. and Lam, P. G. and Burch, M. J. and Li, J. and Rogers, B. J. and Dickey, E. C. and Maria, J.-P.}, year={2014}, month={Aug}, pages={072904} }
 @article{harris_burch_ihlefeld_lam_li_dickey_maria_2013, title={Realizing strain enhanced dielectric properties in BaTiO3 films by liquid phase assisted growth}, volume={103}, ISSN={0003-6951 1077-3118}, url={http://dx.doi.org/10.1063/1.4813270}, DOI={10.1063/1.4813270}, abstractNote={The addition of a liquid-forming flux to barium titanate thin films promotes densification and grain growth, improves nonlinear dielectric properties, and allows residual strain to be sustained in polycrystalline films without cracking at thicknesses relevant to device fabrication. Relative tuning, an excellent indicator of crystalline quality and an important material property for tunable microwave devices, increases from 20% to 70%. Films exhibit 0.15% residual differential thermal expansion mismatch strain, resulting in a shift to the paraelectric-ferroelectric phase transition of 50 °C. This result is in excellent agreement with theory, demonstrating the ability to tune ferroic transitions without epitaxial approaches.}, number={1}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Harris, David T. and Burch, Matthew J. and Ihlefeld, Jon F. and Lam, Peter G. and Li, Jing and Dickey, Elizabeth C. and Maria, Jon-Paul}, year={2013}, month={Jul}, pages={012904} }