Intrinsic magnetic properties of the layered antiferromagnet CrSBr

TL;DR

This study clarifies the intrinsic magnetic properties of CrSBr, confirming its A-type antiferromagnetic order below 131 K and demonstrating strong intra-layer ferromagnetic correlations at higher temperatures, resolving previous debates about its magnetic phases.

Contribution

The paper provides experimental evidence that the low-temperature magnetic transition observed in some studies is extrinsic, and confirms the intrinsic magnetic phase diagram of CrSBr aligns with mean-field theory predictions.

Findings

Absence of the 40 K magnetic transition in high-quality crystals.

Confirmation of A-type antiferromagnetic order below 131 K.

Presence of strong ferromagnetic correlations above TN.

Abstract

Van der Waals magnetic materials are an ideal platform to study low-dimensional magnetism. Opposed to other members of this family, the magnetic semiconductor CrSBr is highly resistant to degradation in air, which, besides its exceptional optical, electronic, and magnetic properties, is the reason the compound is receiving considerable attention at the moment. For many years, its magnetic phase diagram seemed to be well-understood. Recently, however, several groups observed a magnetic transition in magnetometry measurements at temperatures of around 40 K that is not expected from theoretical considerations, causing a debate about the intrinsic magnetic properties of the material. In this letter, we report the absence of this particular transition in magnetization measurements conducted on high-quality CrSBr crystals, attesting to the extrinsic nature of the low-temperature magnetic phase observed in other works. Our magnetometry results obtained from large bulk crystals are in very good agreement with the magnetic phase diagram of CrSBr previously predicted by the mean-field theory; A-type antiferromagnetic order is the only phase observed below the N\'eel temperature at TN = 131 K. Moreover, numerical fits based on the Curie-Weiss law confirm that strong ferromagnetic correlations are present within individual layers even at temperatures much larger than TN.