TEXTURED BUFFER LAYER FOR THE GROWTH OF HIGH TEMPERATURE SUPERCONDUCTOR THIN FILMS ON POLYCRYSTALLINE SUBSTRATES

Power converter operating at cryogenic temperatures requires high critical current (JC) superconducting film in Ni alloys. It has bee shown, however, that YBa2Cu307-8 (YBCO) films deposited directly on these substrate materials exhibit poor superconducting properties at liquid nitrogen temperature because of contamination with diffusing species from the surface. A buffer layer of (001) textured yttria-stablized zirconia (YSZ) as diffusion barrier is needed t grow high JC YBCO thin films. UES proposes to develop a modified magnetron sputter deposition method for the growth of textured YSZ films on Ni alloys. The initial approach will be t follow the recently reported work of Fukutomi et al that demonstrated the formation of textured YSZ film by a modified bias sputtering technique. This technique will be further modified to increase the ion content of the sputtered flux hopefully improving the texturing. The deposited films will be characterized by X-ray diffraction and pole figure analysis. The textured YSZ films will be used as substrates for YBCO deposition using sputtering at UES and laser ablation at the Materials Laboratory of the WPAFB.