Crystal structure and electronic structure of the La _1-x K _x Co _1-x Nb _x O ₃ oxides

The La1−xKxCo1−xNbxO3 oxides were prepared by conventional solid state reaction technique. By using the GSAS programme a successful fit (Rp = 3.45%, Rwp = 2.77%, X2 = 1.28) was obtained, for x = 0.1. Refinements confirmed that K occupying the La sites and Nb for Co sites gave an acceptable occupancy factor for K and Nb. The valence state of all the ions in the system was determined by XPS analysis, and the lattice parameters were calculated according to the results of selected-area-diffraction (SAD) patterns and X-ray diffraction (XRD) identifications. The direction of the superlattice structure along [001] was found for x = 0.1 as identified from the SAD patterns.