Preparation and superconducting properties of Y-Ba-Cu-O films on oxide polycrystalline substrates by chemical vapour deposition

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Abstract
Y-Ba-Cu-O superconducting films were prepared on Y2O3-stabilized ZrO2(YSZ), MgO and Al2O3 polycrystalline substrates by chemical vapour deposition using beta -diketone metal chelates as sources. The c-axis of YBa2Cu3Oy was mainly oriented perpendicular to the plane of the films obtained above 800 degrees C. The films deposited on YSZ and MgO at 850 degrees C showed zero resistivity at 90 K and 87 K, respectively. The superconducting transition temperature of 71 K was the highest among the transition temperatures of the films deposited on Al2O3. The critical current density (Jc) of the film on YSZ was 8.0*103 A cm-2 and that of the film on MgO was 1.0*104 A cm-2 at 77.3 K and 0 T. Jc measured at 77.3 K under an applied magnetic field of 15 T parallel to the film planes was 44 A cm-2 for the film on YSZ and 27 A cm-2 for the film on MgO. The temperature gradients of the upper critical field (-dBc2/dT) determined by the definition of zero resistivity for upper critical field (-dBc2/dT) determined by the definition of zero resistivity for the film prepared on the YSZ substrate were 4.7 T K-1 and 1.0 T K-1 when the magnetic field was parallel and perpendicular to the film plane, respectively.