Anomalous Paramagnetic Magnetization in Mixed State of CeCoIn$_5$ single crystals

TL;DR

This study investigates the mixed-state magnetization of CeCoIn$_5$ single crystals, revealing a suppressed paramagnetic response and a large Zeeman effect, with no vortex anomalies observed.

Contribution

It provides new insights into the paramagnetic behavior and spin susceptibility in the mixed state of CeCoIn$_5$, highlighting the role of heavy electrons and Zeeman effects.

Findings

Paramagnetic magnetization is suppressed in the mixed state.

Spin susceptibility increases with magnetic field.

No vortex response anomalies were observed.

Abstract

Magnetization and torque measurements were performed on CeCoIn$_5$ single crystals to study the mixed-state thermodynamics. These measurements allow the determination of both paramagnetic and vortex responses in the mixed-state magnetization. The paramagnetic magnetization is suppressed in the mixed state with the spin susceptibility increasing with increasing magnetic field. The dependence of spin susceptibility on magnetic field is due to the fact that heavy electrons contribute both to superconductivity and paramagnetism and a large Zeeman effect exists in this system. No anomaly in the vortex response was found within the investigated temperature and field range.