Growth conditions and superconductive properties of a-axis oriented YBa2Cu3O7-δ films on LaSrGaO4 substrates

Summary form only given. In-plane aligned a-axis YBa₂Cu ₃O_7-δ (YBCO) films are needed for the investigation of the anisotropic properties of superconductors and their application to electron devices. However, usually a limited substrate temperature range is necessary for a-axis orientation. In this work the LaSrCaO₄ (LSGO) substrates were treated by ion-beams, then YBCO films were deposited by the temperature gradient method. It was found that surface cleaning by ion beam with 45 degree incident angle was effective. High quality a-axis oriented films were formed at the initial substrate temperature in the range of 520°C-600°C and final temperature of 680°C. In-plane aligned a-axis oriented films were obtained at the initial substrate temperature in the range of 540~570°C. The in-plane aligned films have an anisotropic resistance of factor 21. Many jumps were observed in I-V characteristics along the c-axis which are attributed to the intrinsic Josephson effects