Theoretical study of phase transition in type II superconductors with Pauli paramagnetic effect in high magnetic field

Abstract

High-field phase diagram of type II superconductors with paramagnetic depairing effect is examined through a theoretical argument and a numerical simulation of a Ginzburg–Landau model with a negative quartic term. Our results strongly suggest, contrary to the argument based on magnetization data in CeCoIn 5, that the first-order transition at H c2( T) in the mean field (MF) approximation is reflected in real systems merely as a crossover and that the thermal phase diagram is similar to that in the ordinary case where the MF transition is of second order.