Open AccessThe temperature dependence for the third shell's Fourier‐peak of Nb‐EXAFS in KNbO 3 as additional source of information on the local atomic structure
Author(s) -
Bugaev Lusegen A.,
Shuvaeva Victoria A.,
Zhuchkov Konstantin N.,
Rusakova Elizaveta B.,
Vedrinskii Rostislav V.
Publication year - 2001
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049500016939
Subject(s) - tetragonal crystal system , extended x ray absorption fine structure , octahedron , fourier transform , shell (structure) , crystallography , diffraction , chemistry , materials science , phase (matter) , crystal structure , absorption spectroscopy , optics , physics , organic chemistry , quantum mechanics , composite material
The information on the structure of tetragonal KNbO 3 is extracted from the temperature dependence of the third shell's Fourier‐peak of Nb‐EXAFS. It is shown that this dependence can be explained by two effects: 1) rigid rotations of the O 6 ‐octahedron and 2) increase of the third shell's DW‐parameter. However, diffraction data on the temperature dependence of the DW‐parameter permit us to conclude that the last effect only is sufficient and the O 6 ‐octahedron rotation doesn't occur in the high‐temperature phases of KNbO 3 . Using EXAFS it is revealed that in the neighboring cells Nb‐atoms are parallel shifted closely to [211] direction in tetragonal phase.