Center for Energy Harvesting Materials and Systems (CEHMS). Bio-Inspired Materials and Devices Laboratory (BMDL)Materials Science and EngineeringInstitute for Critical Technology and Applied SciencesOak Ridge National Laboratory. Chemical and Engineering Materials DivisionMaurya, DeepamMurayama, MitsuhiroPramanick, A.Reynolds, William T. Jr.An, KePriya, Shashank2015-05-042015-05-042013-03-21Journal of Applied Physics 113, 114101 (2013); doi: 10.1063/1.4792729Priya, Shashank (2013). Origin of high piezoelectric response in A-site disordered morphotropic phase boundary composition of lead-free piezoelectric 0.93(Na0.5Bi0.5)TiO3-0.07BaTiO(3). Journal of Applied Physics, 113(11). doi: 10.1063/1.47927290021-8979http://hdl.handle.net/10919/51990Perovskite piezoelectric compositions near the morphotropic phase boundary (MPB) are known to exhibit high piezoelectric response. In lead-based ABO(3) compound with B-site disorder, the origin of this enhancement has been associated with the presence of an intermediate monoclinic/orthorhombic state that bridges the adjacent ferroelectric rhombohedral and tetragonal phases. However, the origin of high piezoelectric response in lead-free ABO(3) compounds with A-site disorder has not been conclusively established. We describe a microscopic model derived from comparative analyses of high resolution transmission electron microscopy and neutron diffraction that explains the origin of high piezoelectric response in lead-free MPB compositions of 0.93(Na0.5Bi0.5)TiO3-0.07BaTiO3. Direct observation of nanotwins with monoclinic symmetry confirmed the presence of an intermediate bridging phase that facilitates a pathway for polarization reorientation. Monoclinic distortions of an average rhombohedral phase are attributed to localized displacements of atoms along the non-polar directions. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4792729]10 pagesapplication/pdfen-USIn CopyrightWhiskersPhase transitionsPiezoelectric fieldsFerroelectric phase transitionsFerroelectricityArticle - Refereedhttp://scitation.aip.org/content/aip/journal/jap/113/11/10.1063/1.4792729https://doi.org/10.1063/1.4792729