Pendekatan Persamaan Ginzburg – Landau dalam Superkonduktifitas Tipe II[APPROXIMATION OF GINZBURG – LANDAU EQUATIONS IN TYPE II SUPERCONDUCTIVITY]

Abstract

The Ginzburg-Landau (GL) equation is applied for the type II superconducting materials. To simplify the complex situation, the mobility of vortices is firstly reduced by pinning them. The pinning term is then introduced into the equation. An equilibrium state in GL theory corresponds to a critical point of the Helmholtz free-energy functional. The model has been justified by the microscopic theory of Bardeen – Cooper – Schrieffer (BCS theory), by introducing the local density of superconducting electron pairs, called “Cooper pairs”. For the dynamic condition of vortices, the theory uses Schrödinger-type dynamics for the order parameter coupled to a Maxwell-type equation for the magnetic field potential leading to the Schrödinger -Ginzburg-Landau (SGL) model as well as time-dependent Ginzburg Landau (TDGL) functional. Finally the diagmagnetism of Meissner effect, of which the magnetic field is expelled from the superconductor, is also accommodated.