Generalized Ginzburg-Landau equation and the properties of superconductors with Ginzburg-Landau parameter #kappa# close to 1

摘要

An expression is derived for the free energy of a superconductor near the critical temperature, taking account of the terms of next highest order in the parameter 1-T/T_c. These terms become important for Ginzburg-Landau parameter values |#kappa# - 1| 1, and in this case, in an external magnetic field H_0 close to H_(c2), the structure of the order parameter is determined by the relative values of the three small parameters |#kappa# - 1|, 1 - T/T_c, and (H_(c2) - H_0)/H_(c2). Three types of lattices are investigated: triangular with one and two flux quanta per cell and square with one flux quantum per cell.