We review results obtained from recent neutron scattering studies of the lead-oxide class of perovskite relaxors PMN and PZN. A ferroelectric soft mode has been identified in PMN at 1100 K that becomes overdamped near 620 K. This is the same temperature at which polar nanoregions (PNR) begin to form, denoted by Td , and suggests that a direct connection exists between the soft mode and the PNR....

This thesis describes a series of studies undertaken to explore the criteria for the stabilization of Bi3+ in a perovskite through the formation of mixed A-site solid solutions. Electronically similar to Pb2+ but with a smaller ionic radius, Bi3+ has the potential to replace and improve upon Pb-based counterparts for dielectric and piezoelectric applications. Building off the discovery that Bi(...

Simultaneous manipulation of multiple boundary conditions in nanoscale heterostructures offers a versatile route to stabilizing unusual structures and emergent phases. Here, we show that stable supercrystal phase comprising three-dimensional ordering domains with tailored periodicities can be engineered PbTiO3–SrRuO3 ferroelectric–metal superlattices. A combination laboratory synchrotron X-ray ...

Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li-O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity.

Density functional theory study of hypothetical PbTiO3-based oxysulfides John A. Brehm,* Hiroyuki Takenaka,† Chan-Woo Lee,‡ Ilya Grinberg,§ Joseph W. Bennett,‖ Michael Rutenberg Schoenberg,¶ and Andrew M. Rappe# The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadelphia, Pennsylvania 19104-6323, USA (Received 13 November 2013; re...

PbTiO3-BiScO3 ceramics possess high piezoelectricity and Curie temperature simultaneously, presenting a very promising candidate for high-temperature actuators transducers. Figuring out the underlying piezoelectric mechanisms is of great importance its application. Herein, we reveal quantified intrinsic extrinsic contributions to electrostrain morphotropic composition with phase coexistence by ...

According to recent experiments and predictions, the orientation of the polarization at the surface of a ferroelectric material can affect its surface chemistry. Here we demonstrate the converse effect: the chemical environment can control the polarization orientation in a ferroelectric film. In situ synchrotron x-ray scattering measurements show that high or low oxygen partial pressure induces...

Using an extension of a first-principles method developed by King-Smith and Vanderbilt Phys. Rev. B, 49, 5828 1994 , we investigate the effects of in-plane epitaxial strain on the ground-state structure and polarization of eight perovskite oxides: BaTiO3, SrTiO3, CaTiO3, KNbO3, NaNbO3, PbTiO3, PbZrO3, and BaZrO3. In addition, we investigate the effects of a nonzero normal stress. The results ar...