Ginzburg-Landau theory of the superheating field anisotropy of layered superconductors

TitleGinzburg-Landau theory of the superheating field anisotropy of layered superconductors
Publication TypeJournal Article
Year of PublicationSubmitted
AuthorsLiarte, Danilo B., and Sethna James P.

We investigate the effects of material anisotropy on the superheating field of layered superconductors. We provide an intuitive argument both for the existence of a superheating field, and its dependence on anisotropy, for κ=λ/ξ (the ratio of magnetic to superconducting healing lengths) both large and small. We see that the superheating field shows significant anisotropy only when the anisotropy is large and the Ginzburg-Landau parameter κ is small. We then conclude that only small anisotropies in the superheating field are expected for typical unconventional superconductors near the critical temperature. Using a generalized form of Ginzburg Landau theory, we do a quantitative calculation for the anisotropic superheating field by mapping the problem to the isotropic case, and present a phase diagram in terms of anisotropy and κ, showing type I, type II, or mixed behavior (within Ginzburg-Landau theory), and regions where each asymptotic solution is expected. We estimate anisotropies for a number of different materials, and discuss the importance of these results for radio-frequency cavities for particle accelerators.



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