Fabrication of SrMO3 (M = Ce and Zr) thin films and SrCeO3SrZrO3 superlattices by laser ablation

Perovskite-type oxides SrMO3 (M:Ce and Zr) thin films and SrCeO3SrZrO3 superlattices have been made by ArF excimer laser ablation method. These materials incorporate a large amount of protons and are well known as proton conducting solid electrolytes. The scanning electron microscope observations reveal that thin films with smooth surface can be grown on (110) surface of MgO substrates. In contrast, only polycrystalline thin films can be grown on (100) surface of MgO substrates, which has been often used for the dielectric film growth. This result would be attributed to the large distortion of crystal structures of these materials from the ideal perovskite. From the result of Raman spectra and the electric conductivity measured on SrZrO3 thin films, we found that the concentration of oxygen vacancies decrease with annealing in H2O-vapor atmosphere.