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Pressure‐induced phase transitions in antiferroelectric CsBi(MoO 4 ) 2
Author(s) -
Ma̧aczka M.,
Paraguassu W.,
Souza Filho A. G.,
Freire P. T. C.,
Melo F. E. A.,
Mendes Filho J.,
Hanuza J.
Publication year - 2005
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1270
Subject(s) - antiferroelectricity , raman spectroscopy , phase transition , phase (matter) , ambient pressure , high pressure , chemistry , crystallography , materials science , condensed matter physics , thermodynamics , ferroelectricity , physics , optics , organic chemistry , optoelectronics , dielectric
The high‐pressure Raman spectra of antiferroelectric CsBi(MoO 4 ) 2 were measured at room temperature. These studies indicated that this crystal exhibits two pressure‐induced phase transitions at 0.6 and 1.0 GPa. The stable phase in the 0.6–1.0 GPa range was identified as having the same structure as the ambient‐pressure ferroelastic phase observed below 125 K. The transition at 1.0 GPa is connected with significant distortion of the MoO 4 2− tetrahedra and Bi 3+ coordination sphere. The results suggest that the phase above 1.0 GPa may have the same structure as the high‐pressure phase observed in KDy(MoO 4 ) 2 , KY(MoO 4 ) 2 and KTb(MoO 4 ) 2 crystals. Upon releasing pressure, the high‐pressure phase transforms directly into the ambient‐pressure phase. The origin of the observed suppression of the intermediate phase is discussed. Copyright © 2004 John Wiley & Sons, Ltd.