Mismatch of conductivity anisotropy in the mixed and normal states of type-II superconductors

A. A. Bespalov; A. S. Mel'nikov

doi:10.1103/PhysRevB.85.174502

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Mismatch of conductivity anisotropy in the mixed and normal states of type-II superconductors

A. A. Bespalov, A. S. Mel'nikov

DOI 10.1103/PhysRevB.85.174502 · Physical Review B

T1

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Abstract

We have calculated the Bardeen-Stephen contribution to the vortex viscosity for uniaxial anisotropic superconductors within the time-dependent Ginzburg-Landau (TDGL) theory. We focus our attention on superconductors with a mismatch of anisotropy of normal and superconducting characteristics. Exact asymptotics for the Bardeen-Stephen contribution have been derived in two limits: (i) lEab≪ξab, lEc≪ξc and (ii) lEc≫ξc, lEab≲ξab, where lEab, lEc and ξab, ξc are the electric field penetration lengths and the coherence lengths in the ab plane and in the direction of the c axis. Also, we suggest a variational procedure which allows us to calculate the vortex viscosity for superconductors with arbitrary parameters ξ and lE. The approximate analytical result is compared with numerical calculations. Finally, using a generalized TDGL theory, we prove that the viscosity anisotropy and, thus, the flux-flow conductivity anisotropy may depend on temperature.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
PrFeAsO0.7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
Ba1-xKxFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
BaFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown