マンガンテルル化物のバルクオルターマグネティズムを実証（Bulk Altermagnetism in Manganese telluride）

2025-10-30 マックス・プランク研究所

マックス・プランク固体化学物理学研究所（MPI CPfS）は、マンガンテルル化物（MnTe）で「バルク・オルターマグネティズム（bulk altermagnetism）」を初めて実験的に確認したと発表した。Claire Donnelly率いる国際チームは、X線磁気円二色性を用いた透過型ナノイメージングで、MnTe結晶内部のオルターマグネティック・ドメインとナノ構造を可視化。従来薄膜でのみ観測されていた現象を体積試料で実証した。オルターマグネットは反強磁性秩序を持ちながら強磁性のようなスピントロニクス特性を示し、エネルギー変換や情報処理応用の新素材として注目される。

Schematic of X-ray magnetic circular dichroic scanning transmission x-ray microscopy, with the experimental observation of altermagnetic domains and topological nanotextures in MnTe.© MPI CPfS / C. Donnelly

＜関連情報＞

バルクMnTeで明らかになった反磁性ナノテクスチャー Altermagnetic nanotextures revealed in bulk Mn⁢Te

Rikako Yamamoto, Luke Alexander Turnbull, Marcus Schmidt, José Claudio Corsaletti Filho, Hayden Jeffrey Binger, Marisel Di Pietro Martínez, Markus Weigand, Simone Finizio, Yurii Prots
Physical Review Applied Published: 16 September, 2025
DOI: https://doi.org/10.1103/dp7v-qszq

Abstract

Altermagnetism represents a magnetic phase in which the combination of compensated antiferromagnetic order with an anisotropic crystal field leads to time-reversal symmetry breaking. The resulting combination of properties typically associated with ferromagnets, but with net-zero magnetization, has generated significant interest for both fundamental research and technological applications. With many candidate altermagnetic materials, Mn⁢Te 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 Mn⁢Te 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 Mn⁢Te. Quantitative analysis of the XMCD signal reveals 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 characterize 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.