Takashi Shimano

Properties of YBCO thin films on vicinally polished MgO substrates

YBa2Cu3O7-x thin films were grown on vicinally polished MgO(001) substrates using a reactive RF-magnetron sputtering technique. The authors studied effects of vicinal cut on growth orientations and transport properties. The c-axis directions of all the films were strongly influenced by the substrate surface normal, with weak alignment to the substrate (001)MgO direction. No significant dependence of Tcs on vicinal angles was observed. However, Jcs were strongly degraded with vicinal angle. Jcs were also anisotropic to the vicinal direction. A vicinal cut affected the growth of YBCO films to increase the density of weak links.

Preparation of YBCO Thin Films Using an Off-Axis Sputtering Technique

YBa2Cu3O7-x thin films were deposited on MgO(100) substrates using an off-axis sputtering technique. We investigated the compositional dependence of the substrate position. When the distance between substrate and target center, x, was smaller than 50mm, a considerable deviation from stoichiometry was recognized. As x increased in the region of x>50mm, ratios of Cu/Y and Ba/Y increased slightly, while a ratio of Cu/Ba remained constant. We obtained Tc 0 =80K and Jc(77K,0T)=1×105A/cm2. Surface resistance of the film was 700mΩ at 77K and 9.6GHz.