Growth and superconducting properties of YBCO $(Y_1Ba_2Cu_3O_{7-x}) film on a YSZ single crystal cylinder and a Ni ring were studied. Aim of this study is that how and how much the YBCO film on a cylinder and a Ni tube can shields magnetic field.
High current can flow if grains of YBCO film are well aligned. For the high current application of YBCO films, ab-axes of YBCO film should be aligned within 10°, which can be established by controlling bufferlayer thickness on YSZ and texturing a Ni substrate.
First, we deposited YBCO on a [001] tilt YSZ plat substrate and found that the optimum thickness of bufferlayer is about 15Å. We could control the growth direction and in-plane texture of YBCO film. In low deposition temperature and thick $CeO_2$ bufferlayer YBCO grew parallel to the direction of the tilt substrate axis, and in high deposition temperature and thin think $CeO_2$ (less than 15Å) bufferlater YBCO grew normal to the substrate surface.
Second, we have c-axis normal and well textured YBCO film grown on a curved YSZ substrate, of which [001] axes are continuously inclined, which is confirmed by XRD 2θ,φ-scan measurement.
Third, we applied this technique to YSZ single crystalline cylinder. we measured the trapped field of 0.06 Gauss at 77K. the critical density is about $10^4A$/cm^2.
Finally, a textured Ni tape was used as a substrate. In general, polycrystalline film on a polycrystal substrate, and textured film can grow on a textured substate. We textured Ni by rolling and annealing, on which YBCO film grew textured. Ni tapes were bonded to the shape of a ring and buffered by $CeO_2/YSZ/CeO_2$ layers. Then YBCO deposited on it. The shielded field was measured by the Hall probe putted in the center of the ring. When magnetic field was applied, the ring show the hysteric behavior. And the cirtical current density of a ring is about $10^4A$/㎠. When the external current pulse, 0.6A, was applied, the ring showed a nonlinear response, which will be studied in the future.
