Enhancement of the spin-orbit torque in a Pt/Co system with a naturally oxidized Co layer
Enhancement of the spin-orbit torque in a Pt/Co system with a naturally oxidized Co layer
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DOI：
10.1063/1.4995292
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发表时间：
2017-09
影响因子：
4
通讯作者：
Y. Hibino;T. Hirai;Keisuke Hasegawa;T. Koyama;D. Chiba
中科院分区：
文献类型：
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作者：
Y. Hibino;T. Hirai;Keisuke Hasegawa;T. Koyama;D. Chiba
我们研究了铁磁Co层表面氧化对电流感生自旋轨道力矩的影响。在Pt底层上沉积Co薄膜，期望通过自旋霍尔效应产生自旋电流。这两个阻尼和场的扭矩定量确定使用谐波霍尔电压测量明显增强与自然氧化的Co层的样品。尽管氧化体系具有更大的垂直磁各向异性和几乎相同的面积磁化强度值，即，在与未氧化样品相同的有效铁磁厚度下，磁化转换所需的电流大大降低。结果清楚地表明，沉积在重金属层上的铁磁薄膜的表面氧化在增大自旋-轨道力矩中起着重要作用。
We investigated the effect of surface oxidation of a ferromagnetic Co layer on current-induced spin-orbit torque. A Co thin film was deposited on a Pt underlayer, for which the spin current was expected to be generated through the spin Hall effect. Both the damping- and field-like torques quantitatively determined using harmonic Hall voltage measurements were clearly enhanced in the sample with the naturally oxidized Co layer. Even though the oxidized system possessed a larger perpendicular magnetic anisotropy and nearly the same areal magnetization value, i.e., the same effective ferromagnetic thickness, as those of the unoxidized sample, the electrical current required for magnetization switching was greatly reduced. The results clearly show that surface oxidization of a ferromagnetic thin film deposited on a heavy metal layer plays an important role in enlarging spin-orbit torque.