Superconducting and structural properties of in-plane aligned a-axis oriented YBa2Cu3O7−x thin films

Abstract

We report the superconducting and structural properties of a-axis oriented YBa2Cu3O7−x (YBCO) films as a function of deposition temperature of PrBa2Cu3O7−x (PBCO) template layers. X-ray diffraction (XRD) analysis revealed the orientation relationship in which the b axis of the PBCO template layers and the a axis of the YBCO films were normal to the LaSrGaO4 (100) substrate surface. In-plane aligned a-axis oriented YBCO films having a zero resistance temperature of 88 K and an anisotropy ratio of resistivity of 11.5 at 275 K were obtained on PBCO template layers deposited at 630 °C among the deposition temperatures ranging from 600 to 650 °C at intervals of 10 °C. The degree of in-plane alignment of the a-axis oriented YBCO films which was estimated by the ratio of relative intensity at 90° and 180° in the XRD φ scan of the (102) YBCO peak was 0.5, 0.045, and 0.053 for the films on PBCO templates deposited at 620, 630, and 640 °C, respectively. In conclusion, the deposition temperature of PBCO template layers is critical to fabricate the in-plane aligned a-axis oriented YBCO films on LaSrGaO4 (100) substrates.