Studies on chemical Vapor Deposition of High-temperature Superconductor for Wire Application

点击翻译按钮获取中文摘要

Chemical vapor deposition (CVD) of Y-Ba-Cu-O superconductiong oxide were investigated for production of superconducting wires. The substrates used were polycrystallne Y_2O_3-stabilized ZrO_2 (YSZ), MgO, Al_2O_3, and Hastelloy from which long fibers and tapes can be shaped. The c-axis of YBa_2Cu_3Oy was mainly oriented perpendicular to the subtrate plane. The films deposited on YSZ, MgO and YSZ-coated Hastelloy metal showed zero resistivity at 90 K, 87 K and 87 K, respectively. The superconducting transition temperature of the films deposited on Al_2O_3 and Hastelloy without the YSZ coating layer was below 77 K. The critical current density (J_c) of the films deposited on YSZ was 8.0X10^3 A/cm^2 and that of the film on YSZ-coated Hastelloy was 6.4X10^6 A/cm^2 at 77.3 K and O T. J_c measured at 77.3 K under an applied magnetic field of 15 T parallel to the substrate plane was 6.4X10^3 A/cm^2 for the film on YSZ and 4.7X10^2 A/cm^2 for the film on YSZ-coated Hastelloy.High-J_c Y-Ba-Cu-O superconducting films were successfully prepared at 700ﾟC by CVD under low oxygen partial pressure during film depostition. Such high-J_c films could previously be obtained only at 850ﾟC by CVD.