Growth and Characterization of CeO2Films on Sapphire Substrates by Sputtering Process

Two-inch-diameter CeO2films on R-plane (1*BAR*1*BAR*02) sapphire substrates have been prepared using an on-axis rf magnetron sputtering method. The effects of postannealing treatment, sputtering gas pressure and substrate temperature on the orientation, crystallinity and surface morphology of the CeO2films have been investigated. The (100)-preferred CeO2films with high crystallinity are grown at 820° C and 0.15 Torr and have a full width at half-maximum value of the rocking curve of (200) planes of 0.15°. The spatial variation of thickness of the CeO2films across the 2-inch substrate is about 5.8%. Thec-axis oriented YBa2Cu3Ox(YBCO) films grown on sapphire substrates with a (100)-preferred CeO2buffer layer of 100 nm are made. The YBCO films have superconducting properties with theTcbeing 88–90 K andJc(77 K, 0 T) being (1–3)×106A/cm2.