EPITAXIAL-GROWTH OF YBCO ON HASTELLOY WITH YSZ BUFFER LAYER BY LASER-ABLATION

Good quality superconducting YBa2Cu3O7-delta(YBCO) thin films were gro wn on Hastelloy (Ni-Cr-Mo alloys) with yttria-stabilized zirconia (YSZ ) buffer layers by in situ pulsed laser deposition in a multi-target p rocessing 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 int erdiffusion problems between metallic substrates and superconducting o verlayers. To overcome this difficulty, it is necessary to use YSZ buf fer 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 crystalli nity of YBCO films on metallic substrates, YSZ buffer layers were grow n 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-resistanc e critical temperature of about 83 K. (C) 1998 Elsevier Science S.A.