J. Phys. Colloques 47 (1986) C8-757-C8-760
EXAFS AND XANES STUDIES ON La1-xSrxCoO3 COMPOUNDS (x=0, 0.2, 0.5)H . KAGEYAMA1, N. KAMIJO1, M. NARUKAWA2, F . MARUYAMA2, Y. NAKAO2 et K. TANIGUCHI2
1 Government Industrial Research Institute, Osaka, Ikeda, Osaka 563, Japan
2 Osaka Electro-communication University, Neyagawa, Osaka 573, Japan
The local structure around the Sr and the Co atoms in the title compounds calcined at 850°C-900°C were investigated by EXAFS and XANES spectroscopy. Both the main absorption peak and the threshold energy of Sr K-edge of La0.5Sr0.5CoO3 at 300 K was found to be shifted to lower energy by about 2 eV as compared with that measured at 60 K. The coordination number of the oxygen around the Sr atom of La0.5Sr0.5CoO3 reduced from 11.1 at 60 K to 6.7 at 300 K, and that of La0.8Sr0.2CoO3 also decresead from 12.0 at 60 K to 8.5 at 300 K. There was little difference between the XANES regions of Co K-edge and the coordination numbers of the oxygen around the Co atoms of three compounds at 60 K and 300 K. The oxide ion vacancy localized around the Sr atom already existed at 300 K before reaching to the higher temperature that was reported to be enough for the creation of the oxide ion vacancy.