SUPERCONDUCTING CHARACTERISTICS AND EPITAXIAL-GROWTH ANALYSES OF YBA2CU3O7-X THIN-FILMS BY DIRECT-CURRENT MAGNETRON SPUTTERING

Using direct-current magnetron sputtering deposition, we have successf ully prepared high-quality epitaxial YBa2Cu3O7-x thin films, on (100) and (110) ZrO2, SrTiO3 and LaAlO3 substrates. The films reached zero r esistance at about 90 K and had a critical current density, J(c) (at 7 7 K, H = 0), above 10(6) A cm-2. Electrical measurements showed that t he films had a small microwave surface resistance. The epitaxial struc ture of the films was studied by X-ray diffraction (XRD), Rutherford b ackscattering. (RBS) and channeling spectroscopy, X-ray double-crystal line diffraction and transmission electron microscopy (TEM). It was fo und that the c-axis of the film grown on the (1 00) substrates under o ptimum deposition conditions was perpendicular to the substrate surfac e. But on the (110) substrates, epitaxial growth was along the (110) o r (103) direction. The experimental results indicate that the films ha d excellent superconducting properties and complete epitaxial structur e.