London penetration depth of Fe-based superconductors

Abstract

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. Fe-based superconductors are superconductors whose containing iron compounds and having a very high critical magnetic field. London penetration depth can assist in the study of the behavior of the critical magnetic field. The London penetration depth is the distance to which a magnetic field penetrates into a superconductor and becomes equal to 0. 367879 times that of the magnetic field at the surface of the superconductor. In this paper, the London penetration depth λ(T)of Fe-based superconductors is studied by Ginzburg-Landau scenery. Free energy of Fe-based superconductors is assumed by modified the free energy of two-band magnetic superconductors model and theλ (T)of Fe-based superconductors is derived analytically. Finally, the temperature dependence of Δλ (T) = λ (T)- λ (0) is investigated and applied to Single-Crystal Ba(Fe0. 93 Co0. 07)2 As2 superconductors. © (2014) Trans Tech Publications, Switzerland.