CHARACTERISTICS OF HIGH-TC SUPERCONDUCTING THIN-FILMS PREPARED BY CHEMICAL VAPOR-DEPOSITION

Superconducting YBa2Cu3O7-x thin films were prepared by chemical vapor deposition (CVD) using beta-diketonate chelates on single-crystalline SrTiO3, MgO substrates and metal ones. The best films on single-crystalline MgO had the zero resistance T(c) at 89K and J(c) above 3.6x10(4)A/cm2 (at 77.3K, OT). And on SrTiO3, T(c) at 92.5K and J(c) above 2.0x10(5)A/cm2. According to an X-ray diffraction (XRD) pattern, the orthorhombic crystal structures oriented c-axis had been confirmed. Magnetic field dependence on J(c) of the YBCO film was measured at 77.3K. J(c) depends on the angle between the direction of applied field and that of the c-axis of YBCO. 10 cm long superconducting tapes were obtained by CVD using Ni-based alloy as a substrate. These tapes had the crystal structures of YBa2Cu3O7-x oriented (110) and T(c) at 84.5K. The strain dependence of J(c) was measured. Bending strain up to 0.08% did not reduce J(c).