在室温下的非线性反铁磁体中出现大的异常霍尔效应
Satoru Nakatsuji1,2, Naoki Kiyohara1, Tomoya Higo1
1Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan.
Nature
|November 3, 2015
概括
研究人员在抗铁磁体Mn3Sn中发现了一个巨大的异常霍尔效应,即使磁化程度最小. 在没有强磁场的情况下, 提供一种控制电子属性的新方法.
科学领域:
- 凝聚物质物理学
- 材料科学
- 机器人
背景情况:
- 异常的霍尔效应 (AHE) 通常在铁磁材料中观察到,并且与磁化成比例.
- 抗铁磁体通常不会在零磁场中表现出显著的AHE,因为它们的净磁化消失.
- 最近的理论表明,AHE可能通过贝里相概念在反铁磁体和自旋液体中发生,独立于净磁化.
研究的目的:
- 在没有净自转磁化的反铁磁材料中调查异常霍尔效应的存在和大小.
- 探索抗铁磁体在没有强磁场的情况下需要显著的霍尔效应的应用中的潜力.
主要方法:
- 在Mn3Sn中测试霍尔导电性,这是一种具有非线性自旋结构的反铁磁体.
- 描述Mn3Sn的磁性特性,包括其弱铁磁矩.
- 研究Mn3Sn中异常霍尔效应的场依赖反应.
主要成果:
- 在Mn3Sn中观察到很大的异常霍尔导电性,在室温下达到~20 (Ω·cm) -1,在低温下达到>100 (Ω·cm) -1.
- 观察到的AHE大小与铁磁金属中的AHE大小相当.
- 由于材料的弱和软铁磁矩,可以使用小磁场 (数百 oersted) 切换霍尔效应信号.
结论:
- 这项研究提供了第一个关于反铁磁体中显著的零场异常霍尔效应的经验证据.
- Mn3Sn的性反铁磁性状态使得它能够产生大型且可切换的AHE,与传统机制不同.
- 这些发现表明在旋转电子学中的潜在应用,特别是在低流失场内存设备中.
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