Mixed-State Thermodynamics of Superconductors with Moderately Large Paramagnetic Effects

TL;DR

This paper investigates how Pauli paramagnetism influences thermodynamic properties in superconductors with vortex states, explaining unusual experimental observations in CeCoIn$_5$ through a quasiclassical approach.

Contribution

It introduces a detailed analysis of paramagnetic effects on thermodynamics in superconductors, highlighting the change in field dependence of specific heat and the temperature behavior of the Maki parameter.

Findings

Sign change in the curvature of specific heat with increasing paramagnetic effects

Maki parameter $ ext{2}$ increases with temperature due to paramagnetic depairing

Provides explanation for anomalous field dependence of specific heat in CeCoIn$_5$

Abstract

Effects of Pauli paramagnetism on thermodynamic quantities in a vortex state, such as the specific heat $C$ and magnetization $M$, are studied using the quasiclassical Eilenberger formalism. We demonstrate that with an increase of paramagnetic depairing effect, the sigh of the curvature of the field dependence of $C$ changes from negative to positive, and that the Maki parameter $\kappa_2$ becomes an increasing function of temperature. Our results provide a natural explanation for the unusual field dependence of $C$ seen in CeCoIn$_5$ in terms of the paramagnetic effect.