X-ray diffraction and Raman spectroscopy studies of BaSrMWO6 (MNi, Co, Mg) double perovskite oxides

In this work we report on the crystal structure and Raman spectroscopy of BaSrMWO 6 (M Ni, Co, Mg) double perovskite oxides. The results showed that the Ni, Co and Mg containing compounds crystallize in a cubic system with the space group Fm-3 m. The double perovskite structure can be represented as a three-dimensional network of alternating MO 6 and WO 6 octahedra, with Ba- and Sr-atoms occupying the interstitial spaces. The Raman spectra of this crystalline perovskite oxides are interpreted by means of factor group analysis in terms of space group Fm-3 m. Assignments of the W O vibrational stretching and bending modes have been made. High temperature Raman spectroscopy of BaSrNiWO 6 showed that all lattice modes illustrate a linear decrease in wavenumbers while temperature is increased. No discontinuities, in the temperature changes, in wavenumber observed for all modes recorded: indicating that the structure remains cubic and stable up the highest temperature studied here.