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Vibrational properties of ferroelectric hexagonal tungsten bronzes AB x W 3− x O 9 , where A = K, Rb, Cs and B = Nb, Ta, Zr, Cr
Author(s) -
Ma̧czka M.,
Hanuza J.,
Majchrowski A.
Publication year - 2001
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.776
Subject(s) - raman spectroscopy , tungsten , crystallography , rubidium , valence (chemistry) , crystal structure , ferroelectricity , x ray crystallography , chemistry , diffraction , materials science , potassium , physics , dielectric , optoelectronics , organic chemistry , optics
Powder x‐ray diffraction, Raman and IR studies were performed for a number of ferroelectric hexagonal tungsten bronzes of the formula AB x W 3− x O 9 , where A = K, Rb, Cs and B = Nb, Ta, Zr and Cr. The observed vibrational modes were assigned to the respective motions of atoms in the unit cell. The x‐ray data revealed that the partial substitution of W atoms by atoms with lower valence results in shortening of the W—W distances within the xy plane and elongation in the z direction. These changes in the crystal structure were correlated with the vibrational data. The measured spectra indicated also the presence of some kind of ordering in the potassium–and rubidium–zirconium bronzes, and the presence of a large number of defects for the chromium bronzes. Copyright © 2001 John Wiley & Sons, Ltd.