THE STUDY ON TEMPERATURE-DEPENDENT SURFACE CRITICAL MAGNETIC FIELD OF IRON-BASED SUPERCONDUCTORS

The upper critical magnetic field (Hc2) is one of the important properties of superconductors in external magnetic field. The higher magnetic field strength, the more superconductivity is maintained. However, the surface critical magnetic field (Hc3) is larger than upper critical magnetic field which the ratio of Hc3 to Hc2 is constant. In this study, we investigated the surface critical magnetic field of the iron-based superconductor using Ginzburg-Landau’s anisotropic two-band method. The surface critical magnetic field was calculated with four temperature-dependent models. Our analytical formula of the surface critical magnetic field obtains the temperature parameters. Finally, the numerical calculation was applied to the experimental data of iron-based superconductors