Structural and electrical properties of SrZr0.95Y0.05O3/SrTiO3 superlattices

Superlattice thin films of a perovskite-type oxide proton conductor SrZr_0.95Y_0.05O₃/SrTiO₃ were fabricated and their structural and electrical properties were investigated. X-ray and electron diffraction analysis reveals that the thin films were epitaxially grown on MgO (001) substrate. High-resolution transmission electron microscopy observation shows that the multilayered structure is uniform and that the interfaces between the different layers are of low roughness. Misfit dislocations are found at the interface, having Burgers vectors in direction a100]. From the local elemental analysis, the interdiffusion of Zr and Ti between layers was not observed, while Mg impurities diffused from the substrate are observed. The in-plane electrical conductivity of the thin films was measured by impedance spectroscopy. The conductivity of the superlattices shows a higher value than a single SrZr_0.95Y_0.05O₃ film. The activation energies of the epitaxial layers show relatively higher value than the corresponding single crystal.