Altermagnetic nanotextures revealed in bulk MnTe

TL;DR

This study provides direct spectroscopic evidence of intrinsic altermagnetic order in bulk MnTe crystals, confirming that altermagnetism is not limited to thin films and demonstrating a new imaging technique for domain analysis.

Contribution

The paper demonstrates the first direct spectroscopic imaging of bulk altermagnetic order in single-crystal MnTe using transmission XMCD, confirming its intrinsic nature.

Findings

Bulk altermagnetism confirmed in MnTe via spectroscopic imaging.

XMCD imaging reveals magnetic domains and textures consistent with altermagnetism.

The technique allows quantitative analysis of altermagnetic order in bulk materials.

Abstract

With many candidate altermagnetic materials, MnTe has emerged as one of the most promising systems, with growing experimental evidence for altermagnetic phenomena. So far, the majority of measurements have been performed on thin-films, or have involved surface measurements. However, the question of altermagnetic order in the bulk system - in the absence of substrate or surface effects - remains. Here we show evidence for bulk altermagnetism in single crystal MnTe, through spectroscopic X-ray microscopy. By performing nanoscale X-ray magnetic circular dichroic (XMCD) imaging in transmission on a 200 nm thick lamella, we observe domains and magnetic textures with a spectroscopic signature characteristic of altermagnetic order, thereby confirming the intrinsic nature of altermagnetism in MnTe. Quantitative analysis of the XMCD signal reveals an excellent agreement with predicted signals, establishing that the altermagnetic order exists throughout the thickness of the lamella and confirming the intrinsic, bulk nature of the state. With these results, we demonstrate that transmission XMCD spectroscopic imaging is a robust, quantitative technique to probe altermagnetic order, providing a means to probe individual altermagnetic domains within complex configurations. This ability to investigate, and characterise altermagnetic order in bulk crystals represents an important tool for the exploration of altermagnetism across a wide range of candidate materials, of key importance for the development of future technologies.