X-ray structural study of ferroelectric KH2AsO4 and KD2AsO4

In order to understand systematically the relationship between the crystal structure and phase transition in tetragonal KH2PO4 (KDP) family, the structures of KH2AsO4 (KDA) and KD2AsO4 (DKDA), which are the end members concerning the transition temperature Tc, have been studied by X-ray diffraction...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2001-08, Vol.70 (8), p.2327-2332
Main Authors: ICHIKAWA, Mizuhiko, AMASAKI, Daisuke, GUSTAFSSON, Torbjörn, OLOVSSON, Ivar
Format: Article
Language:English
Subjects:
Condensed matter: structure, mechanical and thermal properties
Crystalline state (including molecular motions in solids)
Crystallographic aspects of phase transformations
pressure effects
Exact sciences and technology
Physics
Structure of solids and liquids
crystallography
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Summary:In order to understand systematically the relationship between the crystal structure and phase transition in tetragonal KH2PO4 (KDP) family, the structures of KH2AsO4 (KDA) and KD2AsO4 (DKDA), which are the end members concerning the transition temperature Tc, have been studied by X-ray diffraction at room temperature and at Tc+5 K (110 K and 171 K, respectively). It was revealed that the hydrogen-bond distances ROO for KDA and DKDA are longer than those for KDP and DKDP, respectively. These results smear the linear ROO vs Tc relation found earlier in the tetragonal KDP family, contrary to our expectation. The temperature dependence of the bond lengths and angles in KDA and DKDA are compared with those in other members in the family and similarity and difference are discussed.
ISSN:0031-9015
1347-4073
DOI:10.1143/JPSJ.70.2327