Study on local structure around Ce and Gd atoms in CeO2-Gd2O3 binary system.

X-ray absorption spectra near Ce and Gd K-edges of binary oxide of CexGd1-xO(3+x)/2 (0 <= x <= 0.5) in C-type structure solid solution were measured by use of the beamline BL01B1 at SPring-8. Interatomic distances between rear-earth rare-earth and oxygen atoms, RGd-O and RCe-O, were evaluated with the extended x-ray absorption fine structure analysis and found to increase with x. RGd-O was larger than RCe-O by about 0.1 A. Metal-oxygen distances estimated as their linear combinations, xRCe-O + (1-x)RGd-O, well agreed with those determined by X-ray diffraction.