ISSN:
1572-9605
Keywords:
YBa2Cu3O7 thin films
;
microwave surface impedance
;
magnetic field penetration depth
;
parallel-plate resonator
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract Measurements of microwave surface impedance of high-T c films at gigahertz frequencies and nitrogen temperature are performed. A simple technique employing a parallel-plate resonator with liquid nitrogen as a dielectric spaces is suggested. The use of a precise mechanical device provides smooth changing of distance between films from 200μm down to zero. Coupling to the resonator is accomplished by means of two small antennas-half-wave vibrators for frequency 10 GHz. 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. YBa2Cu3O7 films produced by a laser deposition technique on CaNdAlO4 substrates withT c =91 K andj c =107 A/cm2 and on NdGaO3 substrates withT c =91 K andj c =106 A/cm2 are examined, and the valuesR s =0.6 mΩ,λ=348 nm atf=8.97 GHz andR s =0.5 mΩ,λ=250 nm atf=10.12 GHz, respectively, are obtained at 77 K.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00618239
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