Effect of Impurities on the Superheating Field of Type-II Superconductors

Authors

F. Pei-Jen Lin, Old Dominion University
A. Gurevich, Old Dominion UniversityFollow

Document Type

Article

Publication Date

2012

DOI

10.1103/PhysRevB.85.054513

Publication Title

Physical Review B

Volume

85

Issue

5

Pages

054513

Abstract

We consider the effect of nonmagnetic and magnetic impurities on the superheating field H_s in a type-II superconductor. We solved the Eilenberger equations, which take into account the nonlinear pairbreaking of Meissner screening currents, and calculated H_s(T) for arbitrary temperatures and impurity concentrations in a single-band s-wave superconductor with a large Ginzburg-Landau parameter. At low temperatures, nonmagnetic impurities suppress a weak maximum in H_s(T), which has been predicted for the clean limit, resulting, instead, in a maximum of H_s as a function of impurity concentration in a moderately clean limit. It is shown that nonmagnetic impurities weakly affect H_s even in the dirty limit, while magnetic impurities suppress both H_s and the critical temperature T_c. The density of quasiparticles states N(ϵ) is strongly affected by an interplay of impurity scattering and current pairbreaking. We show that a clean superconductor at H = H_s is in a gapless state, but a quasiparticle gap ϵ_g in N(ϵ) at H = H_s appears as the concentration of nonmagnetic impurities increases. As the nonmagnetic scattering rate α increases above α_c = 0.36, the quasiparticle gap ϵ_g (α) at H = H_s increases, approaching ϵ_g ≈ 0.32 Δ₀ in the dirty limit alpha ≫ 1, where Δ₀ is the superconducting gap parameter at zero field. The effects of impurities on H_s can be essential for the nonlinear surface resistance and superconductivity breakdown by strong RF fields.

Rights

© 2012 American Physical Society. All rights reserved.

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Comments

PACS numbers: 74.25.Ha ; 74.25.Op ; 74.78.Na

Original Publication Citation

Lin, F. P.-J., & Gurevich, A. (2012). Effect of impurities on the superheating field of type-II superconductors. Physical Review B, 85(5), 054513. https://doi.org/10.1103/PhysRevB.85.054513

ORCID

0000-0003-0759-8941 (Gurevich)

Repository Citation

Pei-Jen Lin, F. and Gurevich, A., "Effect of Impurities on the Superheating Field of Type-II Superconductors" (2012). Physics Faculty Publications. 903.
https://digitalcommons.odu.edu/physics_fac_pubs/903