Specific heat at the transition in a superconductor with fluctuating magnetic moments

TL;DR

This paper investigates how fluctuating magnetic moments in heavy-fermion superconductors affect the specific heat at the transition, revealing entropy transfer and suppression of magnetic fluctuations below the transition.

Contribution

It demonstrates the coupling between magnetic fluctuations and superconductivity, showing how this interaction influences the transition temperature and specific heat behavior.

Findings

Coupling decreases transition temperature

Increases specific heat jump at transition

Magnetic fluctuations are suppressed below the transition

Abstract

In the heavy-fermion materials CeCoIn$_5$ and UBe$_{13}$, the superconducting order parameter is coupled to flucutating magnetization of the uncompensated part of the localized $f$-moments. We find that this coupling decreases the superconducting transition temperature and increases the jump of the specific-heat coefficient, which indicates entropy transfer from the magnetic to the superconducting degree of freedom at the transition temperature. Below the transition, we find that the magnetic fluctuations are suppressed. We discuss the relation of our results to experiments on CeCoIn$_5$ under pressure.