Premium
X‐ray and electron diffraction studies of the structures of pseudo‐perovskite compounds Pb 2 (Sc,Ta)O 6 and Pb 2 (Mg,W)O 6
Author(s) -
BabaKishi K. Z.,
Cressey G.,
Cernik R. J.
Publication year - 1992
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889892001110
Subject(s) - crystallography , antiferroelectricity , perovskite (structure) , electron diffraction , rietveld refinement , powder diffraction , diffraction , crystal structure , materials science , ferroelectricity , chemistry , dielectric , physics , optics , optoelectronics
Electron diffraction patterns, X‐ray precession patterns and synchrotron Rietveld powder diffraction profiles were used to study the crystal structure of the pseudo‐perovskite compound Pb 2 (Sc,Ta)O 6 (PST). The results of a Rietveld refinement and single‐crystal X‐ray precession studies showed that PST has a lower symmetry than the cubic Fm 3 m in the paraelectric state. The remarkable similarities between the crystal structures of the antiferroelectric Pb 2 (Mg, W)O 6 (PMW) and ferroelectric PST are studied in detail by electron diffraction and it is suggested that PST is a weak or frustrated antiferroelectric oxide. The influence of the degree of structural long‐range order on the existence of an antiferroelectric phase transition in PST and PMW is discussed.