Abstract
Polycrystalline samples with general formula Yb2-xCoxO3 (0 < x < 0.6), obtained by sol-gel method and analysed by X-ray diffraction, formed solid solutions over all the mentioned range. Co showed a maximum solubility of 30 mol% in Yb2O3 sesquioxide. The lattice parameters are found to vary linearly with the composition x. The cationic distribution over the two non-equivalent sites 8b and 24d of the space group la-3 is found to be preferentially. Replacing Yb3+ by Co3+ introduces slight changes in the atomic coordinates leading to an increase of the mean cation-anion distances. The ability of Raman spectroscopy to detect changes in local co-ordination is utilized. A pseudo-tetrahedral coordination for the Co3+ in the 24d site was found. (C) 2009 Elsevier B.V. All rights reserved.