On intrinsic and extrinsic effects in the surface impedance of cuprate superconductors

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Journal of Superconductivity; (United States)

DOI:https://doi.org/10.1007/BF00618132· OSTI ID:7046388

Halbritter, J ^[1]

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1. Kernforschungszentrum, Karlsruhe (Germany)

Surface impedance measurements in the normal and superconducting state are an excellent method to study conduction electron dynamics and extended defects. Electron dynamics show up most clearly in the relaxation range, i.e., for distances traveled in one rf period s = v[sub F]/[omega] (v[sub F] Fermi velocity) being smaller or of the order of the penetration depth [lambda] and mean free path l. For materials with v[sub F][le]10[sup 7] cm/sec the relaxation range is easily accessible for f[ge]0.1 THz. Then, in the normal state, relaxation defines the surface impedance with an intrinsic penetration depth [lambda][sub I] approaching the London penetration depth [lambda][sub L] and R[sub I][approx][mu][sub 0][lambda][sub L]/2[tau] as surface resistance, allowing measurement of [lambda][sub L] and relaxation time [tau](T, [omega]). In the superconducting state the photon interaction scales with [xi][sub F]/[lambda][sub L] = 1/[gamma] ([xi][sub F] dimension of Cooper pairs for l[yields][infinity]) and causes at low frequencies an absorption rate growing with [gamma], which is decreasing with [xi][sub F]/l. The rate increase proportional to [gamma] turns to a decrease above 0.1 THz, which is accompanied by a decrease of [lambda] with frequency which is stronger for large [gamma] and small [xi][sub F]/l. These characteristic dependences allow measurement of material parameters, anisotropy, and dynamics of electrons, especially the relaxation rate [tau]. 19 refs., 6 figs., 1 tab.

• OSTI ID: 7046388
• Journal Information: Journal of Superconductivity; (United States), Journal Name: Journal of Superconductivity; (United States) Vol. 5:4; ISSN JOUSEH; ISSN 0896-1107
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANISOTROPY
COOPER PAIRS
COPPER COMPOUNDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CUPRATES
CURRENTS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
ENERGY LEVELS
EQUATIONS
FERMI LEVEL
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
IMPEDANCE
JOSEPHSON JUNCTIONS
JUNCTIONS
LEAKAGE CURRENT
LONDON EQUATION
MAGNETIC FLUX
MATHEMATICAL MODELS
MICROSTRUCTURE
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RELAXATION
RF SYSTEMS
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VORTICES