AI時代を支える新磁性体、二酸化ルテニウム薄膜の「交代磁性」を実証〜AI・データセンター向け高速・高密度メモリ開発に期待〜

2025-09-24 物質・材料研究機構,東京大学,京都工芸繊維大学,東北大学

図: X線磁気線二色性とスピンの向きで示した単一配向RuO₂薄膜の交代磁性の概念図。

＜関連情報＞

• https://www.nims.go.jp/press/2025/09/202509240.html
• https://www.nims.go.jp/press/2025/09/pg3mvg0000004gma-att/202509240.pdf
• https://www.nature.com/articles/s41467-025-63344-y

交互磁性RuO 2 (101)薄膜における単一バリアントの証拠 Evidence for single variant in altermagnetic RuO2(101) thin films

Cong He,Zhenchao Wen,Jun Okabayashi,Yoshio Miura,Tianyi Ma,Tadakatsu Ohkubo,Takeshi Seki,Hiroaki Sukegawa & Seiji Mitani
Nature Communications  Published:24 September 2025
DOI:https://doi.org/10.1038/s41467-025-63344-y

Abstract

Altermagnetism presents intriguing possibilities for spintronic devices due to its unique combination of strong spin-splitting and zero net magnetization. However, realizing its full potential hinges on fabricating single-variant altermagnetic thin films. In this work, we present definitive evidence for formation of single-variant altermagnetic RuO₂(101) thin films with fully epitaxial growth on Al₂O₃(11‾02) r-plane substrates, confirmed through rigorous structural analyses using X-ray diffraction, atomic-resolution transmission electron microscopy and X-ray magnetic linear dichroism. The mutual correspondence of the occupancy of oxygen atoms on the surfaces of RuO₂(101)[010] and Al₂O₃(11‾02)[112‾0] plays a decisive role in the formation of the single-variant RuO₂, which is also supported by our first-principles density functional theory calculations. We further observed spin-splitting magnetoresistance in the single-variant RuO₂(101)/CoFeB bilayers, highlighting the characteristic effect of single variant on spin transport. The demonstration of single-variant RuO₂(101) films marks a significant advancement in the field of altermagnetism and paves the way for exploring their potential applications.