Crystal structure and dielectric properties of a new complex perovskite oxide Ba2LaSbO6

The crystal structure and dielectric properties of a new perovskite material Ba2LaSbO6 are reported. Ba2LaSbO6 was synthesized for the first time by conventional solid state reaction process. X-ray diffraction (XRD) measurements and Rietveld analysis revealed that, contrary to the other Ba2RESbO6 (RE = Rare-Earth other than La) complex perovskites, which are cubic, Ba2LaSbO6 crystallizes in a monoclinic system having space group P21/n. Dielectric properties of Ba2LaSbO6 at frequencies up to 40 GHz and in temperatures ranging from 50 to 350 K were determined by analyzing the resonant modes in cavities totally filled with the measured material. The dielectric constant (ε')=15.8±0.2% and at 77 K loss factor (tgδ)∼9 x 10-4. Preliminary studies reveal that at the processing temperatures, Ba2LaSbO6 do not react with YBa2Cu3O7-δ (YBCO) and Bi2Sr2CaCu2Ox [Bi (2212)] superconductors. Having appropriate dielectric properties along with chemical stability with superconductors Ba2LaSbO6 can be used as a precursor as substrate for deposition of various passive HTS devices, or as an insulator in the active SIS structures. (orig.)