Microwave studies of granular superconductivity

Author

Portis, A.M. ; Blazey, K.W.

Author_Institution

Dept. of Phys., California Univ., Berkeley, CA, USA

Volume

25

Issue

2

fYear

1989

fDate

3/1/1989 12:00:00 AM

Firstpage

2390

Lastpage

2393

Abstract

Microwave absorption in low magnetic fields is a sensitive contactless indicator of surface granular superconductivity, a significant source of surface resistance. Granularity is also responsible for microwave absorption in the ceramic high-temperature superconductors and in ceramic Chevrel-phase compounds. Modulated microwave adsorption signals from granular ceramics show critical behavior with pinning and depinning of intergranular flux over a modulation cycle. In single crystal YBa₂Cu₃O_7-δ the adsorption arises from the motion of flux within twin-plane domain boundaries. Modulated adsorption signals from these domain boundaries show additional adsorption from fluxon nucleation above critical levels of microwave current. Such losses may contribute significantly to microwave adsorption in zero magnetic field

Keywords

barium compounds; ceramics; flux pinning; high-temperature superconductors; microwave spectra of inorganic solids; surface conductivity; twin boundaries; yttrium compounds; YBa₂Cu₃O_7-δ; ceramic Chevrel-phase compounds; ceramic high-temperature superconductors; critical behavior; depinning; fluxon nucleation; granular superconductivity; high temperature superconductors; intergranular flux; low magnetic fields; microwave adsorption; modulated adsorption; pinning; single crystal; surface granular superconductivity; surface resistance; twin-plane domain boundaries; Ceramics; Contact resistance; Electromagnetic wave absorption; Granular superconductors; High temperature superconductors; Josephson junctions; Magnetic fields; Superconducting films; Surface resistance; Viscosity;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.92788

Filename

92788