Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) and YBa sub(2)Cu sub(3)O sub(7) films on large area MgO and sapphire substrates for high power microwave and rf applications

This paper describes recent work at DuPont to extend the high power microwave performance of YBa sub(2)Cu sub(3)O sub(7) and Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) high T sub(C) superconducting (HTS) films on 2 inch diameter MgO and sapphire substrates. The YBa sub(2)Cu sub(3)O sub(7) films were prod...

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Bibliographic Details
Published in:IEEE transactions on applied superconductivity 1999-01, Vol.9 (2 II), p.2492-2495
Main Authors: Face, Dean W, Pellicone, Frank M, Small, Robert J, Bao, Lijie, Warrington, Mark S, Wilker, Charles
Format: Article
Language:English
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Summary:This paper describes recent work at DuPont to extend the high power microwave performance of YBa sub(2)Cu sub(3)O sub(7) and Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) high T sub(C) superconducting (HTS) films on 2 inch diameter MgO and sapphire substrates. The YBa sub(2)Cu sub(3)O sub(7) films were produced by in-situ off-axis sputtering with radiant substrate heating. The Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) films were produced by off-axis sputtering followed by annealing in oxygen and Tl sub(2)O vapor. The microwave surface resistance and power handling of these films was measured over a wide range of temperature (20 K to 85 K) using an HTS-sapphire resonator technique. At 70 K, the surface resistance of YBa sub(2)Cu sub(3)O sub(7) films on sapphire remained below 250 mu Omega ( 8.1 GHz) for microwave surface current densities up to 1.7 x 10 super(6) A /cm super(2). At 70 K, the surface resistance of Tl sub(2)Ba sub(2)CaCu sub(2)O sub(8) films on MgO remained below 230 mu Omega ( 8.1 GHz) with microwave current densities up to 2x10 super(6) A/cm super(2).
ISSN:1051-8223