Ionic conductivity in new perovskite type oxides: NaAZrMO6 (A = Ca or Sr; M = Nb or Ta)

New oxides of the type, NaAZrMO6 (M = Ca or Sr; M = Nb or Ta), have been prepared by the solid-state reaction technique. Phase identification by powder X-ray diffraction (XRD) shows that NaCaZrMO6 has orthorhombic perovskite type structure (Pnma) and NaSrZrMO6 has cubic perovskite type structure (Pm3m). The grain morphology observation by scanning electron microscope (SEM) shows well-sintered grains. ac impedance spectra and electrical conductivity measurements in air, oxygen and nitrogen atmospheres indicate that they are probable oxide ion conductors with ionic conductivities of the order of 10−3 S cm−1 at 750 °C.