Parallel-plate resonator of variable spacer thickness for accurate measurements of surface impedance of high-critical temperature superconductive films.

Summary

Measurements of microwave surface impedance of high-critical temperature films at gigahertz frequencies and nitrogen temperature are performed. A simple technique employing a parallel-plate resonator with liquid nitrogen as a dielectric spacer is suggested. The use of a precise mechanical device provides smooth changing of distance between films from 200 micrometers down to zero. Coupling to the resonator is accomplished by means of two small antennas (half-wave vibrators for frequency 10 gigahertz). The method for determining resistivity and magnetic field penetration depth was based on the analysis of spacer thickness dependences of the resonator quality factor and frequency. YBCO films produced by a laser deposition technique on calcium-neodymium-aluminium oxide substrates, as well as on neodymium-gadolinium oxide substrates are examined.

Details

  • Original title: Parallel-plate resonator of variable spacer thickness for accurate measurements of surface impedance of high-critical temperature superconductive films.
  • Record ID : 1993-2437
  • Languages: English
  • Source: J. Supercond. - vol. 5 - n. 6
  • Publication date: 1992/12
  • Document available for consultation in the library of the IIR headquarters only.

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