Ion-beam-assisted deposition of biaxially aligned yttria-stabilized zirconia template films on metallic substrates for YBCO-coated conductors

摘要

Biaxially textured yttria-stabilized zirconia (YSZ) films were grown on mechanically polished Hastelloy C276 (HC) substrates by ion-beam-assisted deposition and electron-beam evaporation. The surface root-mean-square (RMS) roughness of the polished HC substrates was approx= 3 nm, as measured by atomic force microscopy (AFM). A water-cooled sample stage was used to hold the substrate temperature below 100 deg C during deposition. RMS roughness of approx= 3.3 nm was measured on the deposited YSZ films by AFM. X-ray pole figures were conducted for texture analysis; in-plane texture measured from YSZ (111) PHI -scan FWHM was 13.2 deg and out-of-plane texture from the YSZ (002) omega -scan FWHM was 7 7 deg. An approx= 10 nm thick CeO_2 buffer layer was deposited on the YSZ film at 800 deg C before YBCO films were ablated by pulsed laser deposition at 780 deg C in a 250 mTorr flowing oxygen environment. Good in-plane texture with FWHM approx= 7 deg was observed in YBCO films. T_c =90 K, with sharp transition, and transport J_c of approx= 2.2 X 10~6 A cm~(-2) were observed in a 0.5 mu m thick 5 mm wide, and 1 cm long sample at 77 K in self-field.