YBaCuO-deposition on metal tape substrates

Ni and Ni-alloy substrates were used for the deposition of YBa₂Cu₃O₇-tape conductors. Cube texture of the metallic substrates was achieved by cold rolling and annealing at temperatures >850°C resulting in well aligned cube texture. Tape samples up to 20 cm in length were heated up to the deposition temperature of 670°C in a reducing Ar/H-gas ambient to remove oxides from the Ni substrate surface. Subsequently, CeO₂-based buffer layers were deposited by vacuum evaporation. YBa₂Cu ₃O₇-films were grown on this tape by thermal co-evaporation and intermittent oxidation in a turntable substrate holder. We obtained transition temperatures up to 87 K and critical current densities at 77 K in excess of 1 MA/cm². Critical current characterization in external magnetic fields revealed an excellent power of resistance. Up to 10 T the critical current dropped only by a factor of two and leveled off at higher fields yielding 45 % of its zero field value even at 15 T