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