Evidence for a New Magnetoelectric Effect of Current-Induced Magnetization in a Toroidal Magnetic Ordered State of UNi$_4$B

TL;DR

This study experimentally confirms a new type of magnetoelectric effect in UNi4B, where electric currents induce magnetization aligned with theoretical predictions, revealing complex magnetic behavior beyond ideal models.

Contribution

The paper provides experimental evidence for current-induced magnetization in UNi4B's toroidal magnetic state, supporting and challenging existing theories.

Findings

Electric currents induce uniform magnetization in UNi4B.

The behavior aligns with theoretical predictions but shows some inconsistencies.

The antiferromagnetic state may not be a simple uniform toroidal order.

Abstract

Magnetization measurements under direct electric currents were performed for toroidal magnetic ordered state of UNi$_4$B to test a recent theoretical prediction of current-induced magnetization in a metallic system lacking local inversion symmetry.We found that each of the electric currents parallel to [$2\bar{1}\bar{1}0$] and [$0001$] in the hexagonal 4-index notation induces uniform magnetization in the direction of [$01\bar{1}0$].The observed behavior of the induced magnetization is essentially consistent with the theoretical prediction; however it also shows an inconsistency suggesting that the antiferromagnetic state of UNi$_4$B could not simply be regarded as a uniform toroidal order in the ideal honeycomb layered structure.