Giant spin Hall angle in the Hensler alloy Weyl ferromagnet Co2MnGa
Giant spin Hall angle in the Hensler alloy Weyl ferromagnet Co2MnGa
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DOI：
10.1103/physrevb.103.l041114
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发表时间：
2021-01-29
影响因子：
3.7
通讯作者：
Shiraishi, M.
中科院分区：
文献类型：
--
作者：
Leiva, L.;Granville, S.;Shiraishi, M.
外尔半金属由于其奇异的拓扑性质在凝聚态物理学中扮演着重要的角色，它们与铁磁性的共存可能会导致增强的自旋相关现象。本文利用横向自旋阀结构中的电自旋注入，在室温下研究了铁磁Weyl半金属Heusler合金Co2 MnGa中的逆自旋霍尔效应（ISHE）.精确地提取该材料中的自旋输运性质，例如自旋极化和自旋扩散长度，以估计自旋霍尔角θ（SH），发现其为-0.19 +/-0.04，并且是铁磁体中报道的最高值。虽然该值与已知重金属的数量级相同，但Co2 MnGa的显著更高的电阻率意味着检测电压的幅度的改进，而其铁磁性质允许通过磁化方向控制SHE的强度。它还表明，Onsager的互易性不适用于这个系统，这是部分归因于不同的自旋依赖霍尔电导率自旋向上和自旋向下的载流子。
Weyl semimetals are playing a major role in condensed-matter physics due to exotic topological properties, and their coexistence with ferromagnetism may lead to enhanced spin-related phenomena. Here, the inverse spin Hall effect (ISHE) in the ferromagnetic Weyl semimetal Heusler alloy Co2MnGa was investigated at room temperature by means of electrical spin injection in lateral spin valve structures. Spin transport properties such as spin polarization and spin diffusion length in this material were precisely extracted in order to estimate the spin Hall angle theta(SH), which was found to be -0.19 +/- 0.04 and is among the highest reported for a ferromagnet. Although this value is on the same order of magnitude of known heavy metals, the significantly higher resistivity of Co2MnGa implies an improvement on the magnitude of detection voltages, while its ferromagnetic nature allows controlling the intensity of SHE through the magnetization direction. It was also shown that Onsager's reciprocity does not hold for this system, which is in part attributable to a different spin-dependent Hall conductivity for spin-up and spin-down carriers.