High-field moment polarization in the ferromagnetic superconductor UCoGe

TL;DR

This study investigates high-field magnetic behavior in the ferromagnetic superconductor UCoGe, revealing a moment polarization at around 50 T and comparing it with URhGe's field-induced phenomena, enhancing understanding of their magnetic and superconducting properties.

Contribution

The paper provides the first detailed high-field magnetization and magnetoresistivity measurements of UCoGe up to 60 T, highlighting a moment polarization and its temperature dependence, and compares these findings with URhGe.

Findings

Moment polarization in UCoGe occurs around 50 T at low temperatures.

Anomalies in magnetization and magnetoresistivity vanish above 30-40 K.

Comparison shows different field-induced magnetic phenomena in UCoGe and URhGe.

Abstract

We report magnetization and magnetoresistivity measurements on the isostructural ferromagnetic superconductors UCoGe and URhGe in magnetic fields up to 60 T and temperatures from 1.5 to 80 K. At low-temperature, a moment polarization in UCoGe in a field $\mu_0\mathbf{H}\parallel\mathbf{b}$ of around 50 T leads to well-defined anomalies in both magnetization and magnetoresistivity. These anomalies vanish in temperatures higher than 30-40 K, where maxima in the magnetic susceptibility and the field-induced variation of the magnetoresistivity are found. A comparison is made between UCoGe and URhGe, where a moment reorientation in a magnetic field $\mu_0\mathbf{H}\parallel\mathbf{b}$ of 12 T leads to field-induced reentrant superconductivity.