部屋温度の非コリネア反鉄磁石における大きな異常ホール効果
Satoru Nakatsuji1,2, Naoki Kiyohara1, Tomoya Higo1
1Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan.
Nature
|November 3, 2015
まとめ
研究者らは,Mn3Sn反鉄磁石において,最小限の磁化であっても,大きな異常なホール効果を発見した. この発見はスピントロニックデバイスの可能性を開き 強い磁場なしで電子特性を制御する 新しい方法を提供します
科学分野:
- 凝縮物質物理学
- 材料科学
- スピントロニクス
背景:
- 異常なホール効果 (AHE) は通常,鉄磁気材料で観察され,磁化に比例する.
- アンチフェロマグネットは,消える純磁化により,通常,ゼロ磁場では有意なAHEを示さない.
- 最近の理論では,AHEは,純磁化から独立して,ベリー相概念を通じて,アンチフェロマグネットとスピン液体で発生することが示唆されている.
研究 の 目的:
- 純スピン磁化なしの反鉄磁性物質における異常なホール効果の存在と大きさを調査する.
- 強い磁場がない場合に重要なホール効果を必要とするアプリケーションのアンチフェロマグネットの可能性を調査する.
主な方法:
- 非コリネアスピン構造の反鉄磁石であるMn3Snにおけるホール伝導性の実験測定.
- Mn3Snの磁気特性の特徴,その弱い鉄磁気モメントを含む.
- Mn3Snにおける異常なホール効果のフィールド依存反応の調査.
主要な成果:
- Mn3Snで大きな異常なホール伝導性が観測され,室温では20 (Ω·cm) −1に達し,低温では100 (Ω·cm) −1に達した.
- 観測されたAHEの大きさは,鉄磁気金属に見られるものと同等である.
- ホール効果のサインは,材料の弱くて柔らかい鉄磁気モメントにより,小さな磁場 (オーステッド数百度) を使用して切り替えることができます.
結論:
- この研究は,反鉄磁石における有意なゼロフィールド異常ホール効果の最初の経験的証拠を提供します.
- Mn3Snのキラルな反鉄磁気状態は,従来のメカニズムとは異なる,大きく切り替え可能なAHEを可能にします.
- この発見は,スピントロニクス,特に低流出フィールドのメモリデバイスにおける潜在的な応用を示唆する.
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