Non-linear microwave surface impedance of epitaxial HTS thin films in low DC magnetic fields

A. P. Kharel*, K. H. Soon, J. R. Powell, A. Porch, M. J. Lancaster, A. V. Velichko, R. G. Humphreys

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


We have carried out non-linear microwave (8 GHz) surface impedance measurements of three YBaCuO thin films in dc magnetic fields Hdc (parallel to c axis) up to 12 mT using a coplanar resonator technique. In zero dc field the three films, deposited by the same method, show a spread of low-power residual surface resistance, Rrcs and penetration depth, A (T = 15 K) within a factor of 1.9. However, they exhibit dramatically different microwave field, Hr; dependences of the surface resistance, Rs, but universal Xs(Hr/) dependence. Application of a dc field was found to affect not only absolute values of R, and Xs, but the functional dependences R,(HTf] and X,(Hr/) as well. For some of the samples the dc field was found to decrease Ra below its zero-field low-power value.

Original languageEnglish
Pages (from-to)2121-2124
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Issue number2 PART 2
Publication statusPublished - 1 Dec 1999

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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