Ni tapes were textured by taking advantage of their secondary recrystallization. Ni tapes were composed of very large grains. Their [001] axes were tilted with respect to the surface and their [010] axes were parallel to the rolling direction. The Ni tapes were very tender. But the Ni tapes could be stiffened by adding impurities by the process of atomic diffusion. $YBCO/CeO_2/YSZ/CeO_2$ films were grown on the Ni tapes. if the thickness of the top buffer layer was more than 5nm, the C axes of YBCO layers had the same orientation of Ni[001] axes and if the thickness of the top buffer layer was less than.5nm, the C axes of YBCO layers had the normal orientation with respect to the surface of Ni tapes.
Superconducting rings were fabricated by the process as follows. First Ni tapes were bonded by the way of atomic diffusion bonding process. the Ni tapes were bonded with 0.3Mpa zig pressure and 1000 ℃ temperature in the vacuum chamber. Second $YBCO/CeO_2/YSZ/CeO_2$ films were grown on the Ni rings. M-H of the superconducting ring was measured and the persistent current was calculated from the M-H loop.
12m long Ni tapes with buffer layers were fabricated. $CeO_2/YSZ/CeO_2$ films were deposited by the thermal evaporation deposition method. The partial pressure of water was maintained during deposition with the range between $1 × 10 ^{-7}$Torr and $2 × 10^{-5}$Torr . The temperature of Ni tapes was 700 ℃ during deposition.
The Plasma effect on superconducting property of YBCO was studied in the DC magnetron sputtering system. Superconducting property of YBCO was deteriorated by incident ion flux and low density of oxygen radical particles. Deposition rate was regulated by the flow of carrier gas, Power and total partial pressure.
$Nd{Ba_2}{Cu_3}{O_{7_ δ}}$films were deposited on the bi-crystals whose symmetric misorientation angles were 24 $^\circ$, 30 $^\circ$, 36.8 $^\circ$, 45 $^\circ$ respectively and $I_c-H$ hysteresis curves were measured and the curves were fitted by modeling. The H- field profile of grain boundary with increasing external filed was different from the H- field profile of grain boundary with decreasing external field. This induced $I_c-H$ hysteresis .
