A reel-to-reel system which allows simultaneous deposition of both sided long length epitaxial CeO₂ buffer layers on biaxially textured Ni-5at.%W tape with direct-current (d.c.) reactive magnetron sputtering method is described. Deposition is accomplished through two opposite holes in the cavity by inverted cylindrical magnetron (ICM) sputtering guns. The films were characterized by means of x-ray diffraction (XRD), and atomic force microscope (AFM). The samples exhibited good epitaixal growth with c-axis perpendicular to the substrate surface for both sides. FWHM values of out-of-plane and in-plane for both sides were 3.2° and 3.1°, 5.3° and 5.1°, respectively. AFM observations revealed a smooth, dense and crack-free surface morphology. Biaxially textured CeO₂ buffer layers up to 100-m length could be fabricated with production speed of about 1.2m/h. A 1-m CeO₂ film was obtained with uniform thickness of 50nm, and Δω of 3-3.5° and ΔΦ of 5-6°. Subsequently YSZ barrier and CeO₂ cap layers were deposited to complete the buffer layer structure via the same process. Epitaxial YBa₂Cu₃O_7-δ (YBCO) films grown by d.c. sputtering technique on the short prototype CeO₂/YSZ/CeO₂/NiW conductors yielded self-field critical current densities (Jc) as high as 1.3MA/cm² at 77K. An Ic values of 103A/cm² was obtained for double-sided YBCO coated conductors.

Date Published: 11 March 2008
PDF: 4 pages
Proc. SPIE 6984, Sixth International Conference on Thin Film Physics and Applications, 69840H (11 March 2008); doi: 10.1117/12.792274

Published in SPIE Proceedings Vol. 6984:
Sixth International Conference on Thin Film Physics and Applications
Wenzhong Shen; Junhao Chu, Editor(s)