Influence of CeO2-Cap Layer on the Texture and Critical Current Density of YBCO Film

Abstract

YBa2Cu3O7 (YBCO) thin films have been fabricated on different textured CeO2-cap layers by pulsed laser deposition (PLD). The texture and critical current density Jc of YBCO thin films have been systematically investigated. Both in-plane and out-of-plane textures of YBCO films and CeO2-cap films were characterized by X-ray diffraction (XRD). And the critical currents of YBCO films were measured by the conventional four-probe method. It was found that the texture and Jc of YBCO films were largely dependent on the texture of CeO2-cap layers under the optimized deposition conditions. With increasing the degree of in-plane and out-of-plane texture of CeO2-cap layers, Jc of YBCO films decreased from 4.23×106 A/cm2 to 0.47×106 A/cm2. The FWHM values of the omega scan rocking curves of YBCO films decreased from 3.71 to 1.84° and the phi scan rocking curves from 6.68 to 4.91° with improvement of CeO2-cap layer texture. Our results indicated that the fabrication of high texture quality of CeO2-cap layer was necessary for the epitaxial growth of high-Jc YBCO films. The high-quality YBCO films which are comparable with those grown on single crystal substrates could be achieved on high textured CeO2-cap layers buffered metal substrates.