Large Spin-Orbit-Torque Efficiency Generated by Spin Hall Effect in Paramagnetic Co-Ni-B Alloys
Large Spin-Orbit-Torque Efficiency Generated by Spin Hall Effect in Paramagnetic Co-Ni-B Alloys
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DOI：
10.1103/physrevapplied.14.064056
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发表时间：
2020-12-17
影响因子：
4.6
通讯作者：
Yuasa, S.
中科院分区：
文献类型：
--
作者：
Hibino, Y.;Taniguchi, T.;Yuasa, S.
自旋霍尔效应是自旋轨道转矩（SOTs）的主要来源，它允许有效的磁化电操纵。到目前为止，自旋霍尔效应的研究主要是利用具有强自旋轨道耦合的材料，如5d过渡金属，而轻元素中的自旋霍尔效应导致弱自旋轨道耦合，通常被认为可以忽略不计。在这里，我们报告了一种有效的自旋霍尔材料，可以使用三维过渡金属，即顺磁状态下的非晶Co-Ni-B合金来实现。尽管该材料中没有使用重元素，但通过谐波霍尔测量，我们估计Co-Ni-B合金的自旋霍尔角约为0.10，与5d过渡金属相当。顺磁性Ni的高自旋霍尔电导率是高效自旋霍尔角的来源。我们还演示了利用自旋霍尔效应在Co-Ni-B合金上进行sot诱导的磁化开关，使用重金属自旋霍尔材料具有相当的开关电流密度。我们的发现提供了一种实现高效和无重元素sot器件共存的方法。
The spin Hall effect is a major source of spin-orbit torques (SOTs), which allow efficient electrical manipulation of magnetization. So far, the spin Hall effect has been investigated using materials with strong spin-orbit coupling, such as 5d transition metals, and the spin Hall effect in light elements, which results in weak spin-orbit coupling, is often considered to be negligible. Here, we report an efficient spin Hall material that can be realized using 3d transition metals, namely, an amorphous Co-Ni-B alloy under a paramagnetic state. Despite no heavy elements being used in this material, we estimate the spin Hall angle of Co-Ni-B alloys to be about 0.10 via harmonic Hall measurements, which is comparable to that of 5d transition metals. A highly efficient spin Hall angle originates from the high-spin Hall conductivity of paramagnetic Ni. We also demonstrate SOT-induced magnetization switching using the spin Hall effect on the Co-Ni-B alloy with comparable switching current density using a heavy-metal spin Hall material. Our findings provide an approach to realize the coexistence between highly efficient and heavy-element-free SOT-based devices.