YSZ BUFFER LAYERS ON TECHNICAL SUBSTRATES FOR HTSC CURRENT APPLICATIONS PREPARED BY AAMOCVD

The achievement of high critical current densities of YBCO deposited o n metallic substrates requires the use of buffer layers serving as dif fusion barrier and epitaxy base, YSZ layers were prepared by AAMOCVD o nto different polycrystalline substrate materials (e.g., silver, nicke l, Inconel 600, Hastelloy C). Their properties were investigated. The cubic YSZ is stable when the Y2O3 content exceeds 8 mol%. Films deposi ted at 650 degrees C and thicker than 0.5 mu m show a distinct [200] t exture independent of the used substrates. Detrimental diffusion does not occur. In-plane texture of the buffer cannot be obtained by the CV D-process in contrast to the IBAD process. The in-plane orientation mu st be brought about by an existing preferential orientation of the sub strate. On single crystals the YSZ films are in-plane oriented. It is planned to transfer this result onto technical substrates. If in-plane texture of technical substrates exists, the production of in-plane or iented buffers should be possible. The YBCO layers deposited on Incone l with a c-axis oriented YSZ buffer are superconducting with critical current densities lower than 10(3) A cm(-2) (77 K, 0 T).