Preparation and characterization of NdBa/sub 2/Cu/sub 3/O/sub y/ thin films

Abstract

C-axis oriented epitaxial NdBa2Cu3Oy thin films on (100) SrTiO3 substrates were prepared by off-axis rf sputtering. Thin films with Tc0=90 K in a deviation of 0.5 K were prepared reproducibly under the optimal depositing conditions. A parabolic relation of Tc0 to c-axis lattice parameter corresponding to a typical electronic phase diagram for high-Tc superconductors was observed, indicating an optimal oxygen content for the best superconductivity. The oxygen out-diffusion and thermal expansion of the films were studied by an in-situ high temperature x-ray diffraction.