Epitaxial growth of YBCO on Hastelloy with YSZ buffer layer by laser ablation

Abstract

Good quality superconducting YBa 2Cu 3O 7− δ (YBCO) thin films were grown on Hastelloy (Ni–Cr–Mo alloys) with yttria-stabilized zirconia (YSZ) buffer layers by in situ pulsed laser deposition in a multi-target processing chamber. Generally, Hastelloy exhibits excellent resistance to corrosion, fatigue, thermal shock, impact, and erosion. However, it is difficult to make films on flexible metallic substrates due to interdiffusion problems between metallic substrates and superconducting overlayers. To overcome this difficulty, it is necessary to use YSZ buffer layer since it will not only limit the interdiffusion process but also minimize the surface microcrack formation due to smaller mismatch between the film and the substrate. In order to enhance the crystallinity of YBCO films on metallic substrates, YSZ buffer layers were grown at various temperatures different from the deposition temperature of YBCO films. On YSZ buffer layer grown at higher temperature than that for depositing YBCO film, the YBCO thin film was found to be textured with c-axis orientation by X-ray diffraction and had a zero-resistance critical temperature of about 83 K.