The Critical Magnetic Field of Anisotropic Two-Band Magnetic Superconductors

TL;DR

This paper analytically derives the critical magnetic fields of anisotropic two-band magnetic superconductors within the Ginzburg-Landau framework, applies findings to Fe-based superconductors, and explains high zero-temperature critical fields.

Contribution

It provides new analytical formulas for critical fields in anisotropic two-band superconductors and connects theoretical results with experimental data for Fe-based materials.

Findings

High zero-temperature critical fields in Fe-based superconductors explained

Temperature-dependent critical fields derived and validated against experiments

Critical field ratio and anisotropy effects characterized

Abstract

The upper and lower critical field, and the critical field ratio of an anisotropic two-band magnetic superconductors in Ginzburg-Landau(GL) scenery is derived analytically. The temperature-dependent on the upper critical field is investigated and applied to Fe-based superconductors. We find that the very high value of zero-temperature upper critical field in Fe-based superconductors can be found in the negative differential susceptibility region. The temperature-dependent upper critical field is presented in two formulas as in the empirical view and in the GL two-band view that agrees with the experiment results.