Exchange bias-like behavior due to hidden local magnetic state in a Weyl semimetal

TL;DR

This paper reveals that hidden local magnetic states in Weyl semimetal Co3Sn2S2 induce exchange bias-like behavior, controllable by magnetic nuclei orientation, with implications for magnetic manipulation in topological materials.

Contribution

It introduces a novel mechanism where local magnetic nuclei cause exchange bias-like effects in a Weyl semimetal, expanding understanding of magnetic behavior in topological systems.

Findings

Hard-magnetic nuclei dominate magnetic reversal.

Sign of exchange bias can be controlled by nuclei orientation.

Local magnetic states are stable above Curie temperature.

Abstract

Magnetic Weyl semimetals, which couple magnetic order with topological features, have emerged as promising candidates for advanced topological-materials-based applications. The switching of magnetization and the driving of domain wall motion play key roles in developing such applications. In this study, we suggest that a type of hard-magnetic nuclei dominates the magnetic reversal and induces an exchange bias-like behavior with a prior magnetic history in the bulk Co3Sn2S2 Weyl semimetal. The sign change of the exchange bias-like behavior can be realized by controlling the orientation of such hard-magnetic nuclei. Remarkably, these nuclei can retain their magnetic orientation at a temperature well above the Curie temperature of this material, suggesting the existence of a local magnetic state with non-zero magnetization and high stability. This local state is potentially related to the spin-orbit polaron reported in this system. Our study offers a new scenario for manipulating the magnetic reversal and offers new insights into the magnetism in this Weyl system.