Preparation of a-Axis Oriented YBCO Films by Template Procedure

A-axis oriented Y-Ba-Cu oxide (YBCO) films with good crystalline quality and high T c ’s comparable to those of c-axis oriented films were successfully prepared on (100) MgO and SrTiO3 substrates by off-axis rf-magnetron sputtering. To grow the YBCO films in the a-axis direction, we adopted a template procedure in which films were grown at a low substrate temperature (T s ) in an initial deposition stage and at a high T s in the residuary deposition stage. By this procedure, we could obtain a-axis films with critical temperatures (T c ) of 75K and 77K on MgO and SrTiO3 substrates, respectively.