Based on a theoretical argument and Monte Carlo simulations of a Ginzburg-Landau model derived microscopically, it is argued that, in type-II superconductors where both the paramagnetic and orbital depairings are important, a strong first-order transition (FOT) at Hc2 expected in the mean field (MF) approximation never occurs in real systems and changes due to the fluctuation into a crossover. The present result explains why a nearly discontinuous crossover at Hc2 with no intrinsic hysteresis is observed only in a clean superconducting material with a singlet pairing and a high condensation energy such as CeCoIn5.
- Paramagnetic and orbital depairings
- Upper critical field
- Vortex phase diagram
ASJC Scopus subject areas
- Physics and Astronomy(all)