EXAFS study of phase transitions in KIO3.
The iodine K-edge EXAFS study of KIO3 was performed to clarify local structural changes on the successive phase transitions. The pair-distribution function of three oxygen atoms in an oxygen octahedron is almost independent on temperature like a covalent bond, whereas that of the other three is gradually reduced with increasing temperature like an ionic bond. The result indicates that iodine and oxygen atoms exist as an IO3- molecule in a pseudo-perovskite-type structure. The anomalous behavior in the Debye-Waller factor for the latter pair-distribution function appears around 50 K, which is associated with the orientational glass transition.
Yagi
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Advanced Research Center of Science and School of Science, Kwansei-Gakuin University, Sanda, Hyogo, Japan.
Umezawa
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Terauchi
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Kasatani
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