X-ray diffraction study of ceramic samples of SrCu1/3Nb1/3O3

Abstract

Ceramic samples of SrCu1/3Nb2/3O3, obtained either by slow cooling or by quenching from 1200°C, were studied by X-ray diffraction using the Rietveld method. The slow-cooled SrCu1/3Nb2/3O3 samples contain one phase with a perovskite structure (RB = 4.14%, tetragonal crystal symmetry, space group P4/mmm, Z = 1, a = 3.935 A, c = 4.124 A), its diffraction peaks being considerably broadened. The samples quenched from 1200°C contain two SrCu1/3Nb2/3O3 forms with a perovskite structure: one of them is oxygen deficient (RB = 3.37%, tetragonal crystal symmetry, space group P4/mmm, Z = 1, a = 3.9687 A, c = 4.0718 A), and the other has no oxygen deficiency (RB = 3.20%, tetragonal crystal symmetry, space group P4/mmm, Z = 1, a = 3.95307 A, c = 4.08935 A).