rf residual losses, surface impedance, and granularity in superconducting cuprates

Journal Article · Sat Dec 15 04:00:00 EST 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.346875· OSTI ID:6172829

Halbritter, J ^[1]

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1. Department of Applied Physics, Stanford University, Stanford, CA 94305 (USA) Kernforschungszentrum, Postfach 3640, 7500 Karlsruhe, West Germany (DE)

The rf residual surface resistance {ital R}{sub res} is an important figure of merit for superconducting microwave devices and for establishing the homogeneity of superconducting surfaces. In granular superconductors not only are high residual rf surface resistance values {ital R}{sub res} observed but also there is strong field dependence of {ital R}{sub res}({ital T},{omega},{ital H}{sub rf}) and the penetration depth {lambda}{sub res}({ital T},{omega},{ital H}{sub rf}), even at very low field levels (of order 1 Oe). These observations can be explained in terms of weak links and insulating interfaces, which provide additional degrees of freedom due to fluxoid motion and electromagnetic strip-line modes. These degrees of freedom cause additional interaction mechanisms with applied rf fields. These mechanisms allow a coherent description of the observed {ital T}, {omega}, {ital H}{sub rf}, and {ital H}{sub dc} dependence of {ital R}{sub res} and {lambda}{sub res} for the granular cuprates and for similar effects in Pb, Nb, Nb{sub 3}Sn, and NbN. In addition, on the basis of such rf data, it is possible to quantify the density of weak links and their critical fields and currents.

• OSTI ID: 6172829
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 68:12; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
COPPER COMPOUNDS
CUPRATES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
GRANULAR MATERIALS
MAGNETIC FIELDS
MAGNETIC FLUX
MATERIALS
MICROWAVE RADIATION
OXYGEN COMPOUNDS
PENETRATION DEPTH
PHYSICAL PROPERTIES
RADIATIONS
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS