Epitaxial MgO buffer layers for YBCO thin films onR-plane

MgO buffer layers were epitaxially grown on R-plane substrates by rf magnetron sputtering using an Mg metal target for high- superconducting thin films. A c-axis oriented MgO film with a smooth and homogeneous surface was obtained at C in an Ar/ mixture under a total sputtering gas pressure of 0.3 Torr with Torr . High- superconducting (YBCO) thin films were prepared on substrates with and without an MgO buffer layer by dc magnetron sputtering. The YBCO film on with an MgO buffer layer was c-axis orientatied perpendicular to the surface and exhibited zero resistivity at K. A depth profile of atomic concentration and interdiffusion for YBCO (3000 Å)/MgO (500 Å)/ was investigated. No diffusion of any atom was observed in the interfaces.