J. Phys. Colloques 47 (1986) C8-761-C8-764
EXAFS AND XANES STUDY ON RARE-EARTH CHROMITES OF Gd1-xSrxCrO3N. KAMIJO1, H. KAGEYAMA1, M. NARUKAWA2, F. MARUYAMA2, Y. NAKAO2, K. TANIGUCHI2 et H. MAEDA3
1 Government Industrial Research Institute, Osaka, Ikeda, Osaka 563, Japan
2 Osaka Electro-Communication University, Neyagawa, Osaka 573, Japan
3 Department of Chemistry, Okayama University, Okayama 700, Japan
EXAFS and XANES measurements are made for Gd1-xSrxCrO3 system (x=0,0.2,0.5) at 60 K and 300 K for Sr K-edge and Gd L3-edge respectively, and for Cr K-edge at 300 K to elucidate their oxygen defect structure and their electric conduction mechanism. It is found that the coordination number of oxygen around the Sr ion in Gd0.5Sr0.5-CrO3 is extremely decreased at 300 K as compared with one of that compound at 60 K. Similar tendency is found in Gd0.8Sr0.2CrO3. The result is consistent with that the threshold eneregy of Sr K-edge in Gd0.5Sr0.5CrO3 at 300 K is shifted to low energy side as compared with one at 60 K. Similar tendency is also found in Gd0.8Sr0.2-CrO3. These results imply that mobility of oxygen ion around Sr ion is increased with elevating temperature even in such low temperature region. Oxygen coordination numbers around Gd ions in Gd1-xSrxCrO3 (x=0.2 and 0.5) are also found to be small as compared with one of GdCrO3.