Anomalous Features in Surface Impedance of Y-Ba-Cu-O Thin Films: Dependence on Frequency, RF and DC Fields

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Two high-quality Y-Ba-Cu-O thin films on MgO substrates have been investigated using the coplanar resonator technique at 8 and 16 GHz. Both films exhibit In anomalous decrease in their surface impedance Z(s) as a function of microwave field H-rf. In zero de field, H-rf-dependences of R-s and X, for both the samples are uncorrelated, and only one of the quantities, R, or X, displays anomalous behavior. Here, application of relatively weak (similar to5 mT) de magnetic fields H-dc can produce a correlated decrease of R-x(H-rf) and X-s(H-rf). The dependences of Z(s) on H-dc in both low and high microwave power regimes were found to be non;monotonic. The frequency dependence of R-s similar to f(n), 1.7


Original languageEnglish
Pages (from-to)3497-3500
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Publication statusPublished - 1 Mar 2001


  • anomalous effects, power-handling capability, nonlinear microwave surface impedance, YBaCuO thin films