Investigation of Upper Critical Magnetic Field (HC2(T )) of NdFeAsO1–xFx by Ginzburg–Landau Two-Band Model at x = 0.2

Abstract

This study uses the Ginzburg–Landau (GL) two-band model to theoretically investigate temperature dependent of the upper critical magnetic field for iron-based superconductor NdFeAsO_1–xF_x (Nd-1111). Plotting of the figures for the perpendicular and parallel upper critical magnetic fields, as well as the angle dependent of the upper critical magnetic field versus the temperature of the superconductor Nd-1111, is effectively achieved. As the temperature rises, the two oriented upper critical magnetic fields progressively decrease and vanish at the superconducting transitional temperature of Nd-1111. In addition, a graphic representation and calculation of Ginzburg–Landau parameters coherence lengths and penetration depths are provided. The previously indicated GL parameters grow as temperature rises and diverge at the superconducting material’s 47 K superconducting transitional temperature. Similarly, the GL characteristic parameter’s phase diagram is displayed against temperature; it diminishes as temperature rises and disappears at its transitional temperature.