The crystal structures of 6 perovskites, Ba(Ce1-xNdx)O3, where x was varied from 0 to 0.2 in steps of 0.04, were deduced from neutron powder diffraction data. The specimens were orthorhombic over the entire doping range, with the space group: Pmcn. Previously reported phase transitions were judged here to be artefacts. Rietveld refinement showed that doping with Nd had little effect upon the average crystal structure. However, a linear dependence upon the dopant concentration was found for the Debye-Waller factors of all of the atoms. It was suggested that this indicated an increase in static disorder with doping. A refinement of the O stoichiometry showed that a negligible saturation of the extrinsic vacancies that were introduced by doping had occurred. The vacancies were found to be localized on only one of the 2 crystallographically independent O atoms.

Oxygen Vacancy Ordering in Neodymium-Doped Barium Cerate. K.S.Knight: Solid State Communications, 1999, 112[2], 73-8