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Incommensurate crystal structure of PbHfO 3
Author(s) -
Bosak Alexei,
Svitlyk Volodymyr,
Arakcheeva Alla,
Burkovsky Roman,
Diadkin Vadim,
Roleder Krystian,
Chernyshov Dmitry
Publication year - 2020
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s205252061901494x
Subject(s) - antiferroelectricity , octahedron , superspace , crystal structure , crystallography , synchrotron , materials science , phase (matter) , diffraction , ion , condensed matter physics , chemistry , ferroelectricity , dielectric , physics , optics , organic chemistry , optoelectronics , supersymmetry , mathematical physics
Controversy in the description/identification of so‐called intermediate phase(s) in PbHfO 3 , stable in the range ∼420–480 K, has existed for a few decades. A synchrotron diffraction experiment on a partially detwinned crystal allowed the structure to be solved in the superspace group Imma (00γ) s 00 (No. 74.2). In contrast to some previously published reports, in the pure compound only one distinct phase was observed between Pbam PbZrO 3 ‐like antiferroelectric and Pm 3 m paraelectric phases. The modulation vector depends only slightly on temperature. The major structure modulation is associated with the displacement of lead ions, which is accompanied by a smaller amplitude modulation for the surrounding O atoms and tilting of HfO 6 octahedra. Tilting of the octahedra results in a doubling of the unit cell compared with the parent structure.