Preparation and characterization of Y2O3 buffer layers and YBCO films on textured Ni tape

The direct deposition of Y2O3 buffer layers on cube-textured nickel tape wa s successfully performed by electron beam deposition using Y metal which ox idized during deposition. The Y2O3 layer exhibited excellent out-of-plane a lignment of FWHM of 2.3 similar to 4 degrees and good in-plane alignment wi th similar to 11 degrees FWHM. Surface morphology, crystal orientation and grain size proved to be quite sensitive to the deposition pressure. The sur face roughness and the grain size increased with increasing deposition pres sure, and the crystal orientation changed from (111)Y2O3 to (100)Y2O3. Subs equently, YBCO superconducting films were deposited on (100)Y2O3 buffer lay ers by co-evaporation deposition and pulsed-laser deposition (PLD), Though a good in-plane alignment, as measured by X-ray phi-scan,was achieved in th e YBCO films, their superconducting characteristics were not so good. The T -c onset was about 84 K for the (001)YBCO by PLD. The crystal alignment and the microstructure of YBCO superconducting films deposited by the two depo sition techniques on cube-textured Ni tapes with Y2O3 buffer layers are com pared.