X-ray absorption near edge structure (XANES) measurements of ceria-based solid electrolytes

The X-ray absorption near edge structure (XANES) spectra of a series of ceria samples doped with trivalent rare earth oxide have been measured at the L-III edges of the dopants and the cerium. These spectra give information on the valency of the excited atom and the geometric structure of the direct neighborhood of this atom. By comparing the XANES spectra of the dopants with those of the pure oxides, differences in thr way the dopants are incorporated into the ceria lattice can be observed. These differences together with the mismatch of the ionic radii of the dopants compared to Ce, seem to be responsible for the decreasing ionic conductivity of the lighter rare earth dopants. For Pr, the spectra indicate a partial oxidation to Pr-44 leading to a reduced conductivity. (C) 2000 Elsevier Science B.V. All rights reserved.