Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectric PbSc0.5Ta0.5O3

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Date
2009-09-28
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Volume Title
Publisher
American Physical Society
Abstract

Pressure-induced structural changes in the canonical relaxor Pb0.78Ba0.22Sc0.5Ta0.5O3 were studied with both in-house and synchrotron single-crystal x-ray diffraction as well as Raman spectroscopy at pressures up to 9.8 GPa. The results reveal that the substitution of Ba for Pb in ABO(3) perovskite-type structures, i.e., the substitution of a two-valent element with an isotropic electron shell for an isovalent element with a stereochemically active lone pair, leads to a "diffuse pressure-induced phase transition," a structural transformation over a broad pressure range, without a well-defined critical pressure point. The smeared phase transition of the average structure results from the existence of local structural deformations in the vicinity of A-positioned Ba cations.

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Keywords
phase-transitions, crystallography, anorthite, Physics
Citation
Welsch, A. -M. ; Maier, B. J. ; Engel, J. M. ; et al., Sep 2009. "Effect of Ba incorporation on pressure-induced structural changes in the relaxor ferroelectric PbSc0.5Ta0.5O3," PHYSICAL REVIEW B 80(10): 104118. DOI: 10.1103/PhysRevB.80.104118