反強磁性体の隠れた磁気構造を原子分解能で解明(Atomic-resolution Electron Magnetic Circular Dichroism Unveils Hidden Magnetic Structures in Antiferromagnets)

2026-03-26 合肥物質科学研究院(HFIPS)

中国科学院合肥物質科学研究院・強磁場科学中心を中心とする国際共同研究チームは、反強磁性体の磁気構造を原子レベルで可視化する新しい電子磁気円二色性(EMCD)法を開発した。収差補正透過型電子顕微鏡と電子エネルギー損失分光を組み合わせ、原子コラム単位で磁気情報を抽出することに成功。DyFeO3やα-Fe2O3で原子スケールの磁気秩序を観測し、さらに界面では1単位格子厚の磁気デッド層も検出した。従来困難だった反強磁性体の微視的解析を可能にし、スピントロニクス材料の設計や界面制御に重要な知見を提供する成果である。

反強磁性体の隠れた磁気構造を原子分解能で解明(Atomic-resolution Electron Magnetic Circular Dichroism Unveils Hidden Magnetic Structures in Antiferromagnets)
Atomic spin model of SmFeO3 (left), atomic-resolution elemental distribution (middle), and atomic-resolution magnetic signal (right). (Image by LIU Yizhou)

<関連情報>

埋没界面における原子スケール反強磁性秩序の磁気円二色性イメージング Magnetic circular dichroism imaging of atomic-scale antiferromagnetic order at a buried interface

Dongsheng Song,Fengshan Zheng,Lin Hao,Lei Jin,Yajiao Ke,Yizhou Liu,Mingliang Tian,Binghui Ge,Rafal E. Dunin-Borkowski & Haifeng Du
Nature Nanotechnology  Published:23 March 2026
DOI:https://doi.org/10.1038/s41565-026-02134-z

Abstract

Magnetic circular dichroism utilizing electrons or X-rays serves as a powerful tool for the investigation of magnetism in ferromagnets, but antiferromagnets pose a severe challenge to the technique due to their vanishing net magnetization. Although transmission electron microscopy has demonstrated the atomic-scale characterization of antiferromagnetism using elastically scattered electrons, separating the weak magnetic signal from the dominant electrostatic background remains challenging, and applicability is largely limited to perfect crystals. Here we develop atomic-column-resolved electron magnetic circular dichroism to resolve antiferromagnetic order using a scanning transmission electron microscope. By exploiting chirality around individual magnetic atomic columns, we localize the magnetic circular dichroism signals around the transmitted electron beam with enhanced strength and signal-to-noise ratio, enabling atomic-column magnetic measurements. Applying this technique to antiferromagnets, we not only distinguish the characteristic G-type and C-type antiferromagnetic orderings in DyFeO3 and α-Fe2O3 but also identify a one-unit-cell-thick magnetic dead layer at the buried DyScO3–SmFeO3 interface. Our work establishes a readily accessible method for atomic-scale magnetic order mapping, with potential applications in fields such as interfacial magnetism, topological magnetism, antiferromagnetism and altermagnetism.

1701物理及び化学
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