A technique for high-power microwave diagnostics of large-area homogeneous HTS films

• Published in: IEEE transactions on applied superconductivity Vol. 9; no. 2; pp. 2125 - 2128
• Main Authors: Reznik, A.N., Vorobiev, A.K., Pavlov, S.A., Parafin, A.E., Isaev, V.A., Gaikovich, K.P.
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.1999
• Subjects: Electrical resistance measurement; High temperature superconductors; Integral equations; Magnetic field measurement; Microwave circuits; Microwave devices; Microwave magnetics; Microwave measurements; Microwave theory and techniques; Surface resistance
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/77.784887

A new technique and measuring equipment for determination of the dependence of HTS surface resistance on a microwave magnetic field amplitude, R/sub s/(H), were developed. The measuring system was an open 36 GHz resonator formed between a spherical metal surface and a flat HTS film. The microwave scheme included a high-power pumping wave circuit and a spectrally separated low-power diagnostic signal circuit. The H structure inhomogeneity on the HTS surface was taken into account. Measurements of the averaged surface resistance <R/sub s/(H)> have shown it to be related with R/sub s/(H) by the integral equation. The technique for solution of the integral equation based on the Tikhonov method extended from the theory of incorrect inverse problems was applied. Some results of R/sub s/(H) measurements for large-area (>35 mm) YBCO films deposited onto NdGaO/sub 3/, LaAlO/sub 3/ substrates are presented and discussed.