Zooming into the coexisting regime of ferromagnetism and superconductivity in ErRh4B4 single crystals

TL;DR

This study investigates the complex coexistence of ferromagnetism and superconductivity in ErRh4B4 single crystals, revealing asymmetric and anisotropic magnetic behavior with unique transition characteristics.

Contribution

It provides detailed high-resolution measurements and a new model explaining the local field inhomogeneity effects in the coexisting phases.

Findings

Superconducting phase transitions occur via discontinuous steps upon warming.

Ferromagnetic transition develops gradually, contrasting with superconducting behavior.

Unusual temperature asymmetry and magnetic anisotropy observed in the coexisting regime.

Abstract

High resolution measurements of the dynamic magnetic susceptibility are reported for ferromagnetic re-entrant superconductor, ErRh$_{4}$B$_{4}$. Detailed investigation of the coexisting regime reveals unusual temperature-asymmetric and magnetically anisotropic behavior. The superconducting phase appears via a series of discontinuous steps upon warming from the ferromagnetic normal phase, whereas the ferromagnetic phase develops via a gradual transition. A model based on local field inhomogeneity is proposed to explain the observations.