Preparation of a-axis oriented YBCO film on CeO/sub 2/ buffered sapphire substrate

The purpose of this research is to control the orientations of the YBCO thin films which were deposited on the sapphire substrate with CeO/sub 2/ buffer layer that was fabricated using ion beam sputtering (IBS) method. The orientations of YBCO thin films were investigated using X-ray diffraction, and the dependence of the degree of a-axis orientation upon the substrate temperature and deposition rate was found. The a-axis oriented YBCO thin films were obtained at substrate temperature below 610/spl deg/C and deposition rate of more than 10 /spl Aring//min. High Tc of 85 K was realized by "temperature gradient" method. The surface of YBCO thin film is characterized by atomic force microscopy (AFM).