反強磁性体を用いたトンネル磁気抵抗効果の理論予測 ～次世代高密度・超高速磁気メモリーの開発に貢献～

2026-04-17 東京大学,JSR株式会社,京都大学,東京都立大学,東北大学,理化学研究所,科学技術振興機構

Mn3Sn/MgO/Mn3Sn 磁気トンネル接合。

＜関連情報＞

• https://www.jst.go.jp/pr/announce/20260417/index.html
• https://www.jst.go.jp/pr/announce/20260417/pdf/20260417.pdf
• https://journals.aps.org/prmaterials/abstract/10.1103/xt7z-sf3x

磁気抵抗効果の第一原理研究マンガン3Sn/MgO/マンガン3⁢Sn反強磁性トンネル接合 Ab initio study of magnetoresistance effect in Mn3Sn/MgO/Mn3⁢Sn antiferromagnetic tunnel junction

Katsuhiro Tanaka, Yuta Toga, Susumu Minami, Satoru Nakatsuji, Takuya Nomoto, Takashi Koretsune, and Ryotaro Arita
Physical Review Materials  Published: 16 April, 2026
DOI: https://doi.org/10.1103/xt7z-sf3x

Abstract

The antiferromagnets with the time-reversal symmetry broken magnetic structures possess a finite spin splitting in the momentum space, and may contribute to a realization of a finite tunnel magnetoresistance (TMR) effect even with magnets with zero net spin polarization. In this paper, we study the TMR effect with the noncollinear antiferromagnet Mn₃⁢Sn whose inverse 120^∘ antiferromagnetic order breaks the time-reversal symmetry. In particular, we employ the representative barrier material MgO as the tunnel insulator, and calculate the TMR effect in the Mn₃⁢Sn⁡(01⁢‾‾1⁢0)/MgO⁡(110)/Mn₃⁢Sn magnetic tunnel junctions (MTJs), which has an optimal geometry for the spin-orbit torque switching of the magnetic configurations. We show that a finite TMR ratio reaching ≳1000% appears in the Mn₃⁢Sn/MgO/Mn₃⁢Sn MTJs, which is due to the spin splitting properties of Mn₃⁢Sn in the momentum space combined with the screening effect of MgO.