LASER DEPOSITION OF YBA(2)CU(3)OY THIN-FILMS ON A METALLIC SUBSTRATE WITH BIAXIALLY TEXTURED YSZ BUFFER LAYERS PREPARED BY MODIFIED BIAS SPUTTERING

By using a modified bias sputtering technique, biaxially-textured YSZ thin films were fabricated on polycrystalline metal substrate as a buf fer layer for deposition of YBCO films. The growth quality of YSZ buff er layers thus obtained was found to determine the texture of subseque ntly grown YBCO films, which in turn governed the current-carrying cap acity of the films. The best films prepared to date gave a T-c of 90K and J(c) of 3X10(5) A/cm(2) at zero field and 77K, which was one order higher than that of YBCO grown on an untextured YSZ buffer layer. In order to improve the growth quality of the YBCO films, a Pt thin layer was inserted between the YSZ buffer and the Hastelloy substrate. The reason is not yet clearly understood but a Pt underlayer as thin as 20 nm appeared very promising for attaining the desired combination of go od transport properties with smooth surfaces in YBCO films.