Layer thickness dependence of spin orbit torques and fields in Pt/Co/AlO trilayer structures
Layer thickness dependence of spin orbit torques and fields in Pt/Co/AlO trilayer structures
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DOI：
10.7567/jjap.54.04dm05
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发表时间：
2014-09
影响因子：
1.5
通讯作者：
Tim Yang;M. Kong;M. Kohda;T. Seki;K. Takanashi;J. Nitta
中科院分区：
文献类型：
--
作者：
Tim Yang;M. Kong;M. Kohda;T. Seki;K. Takanashi;J. Nitta
我们研究了不同 Pt 和 Co 厚度的 Pt/Co/Al2O 三层薄膜中自旋轨道相互作用引起的有效磁场的强度，该磁场源自两种不同对称性的不同机制。通过射频磁控溅射沉积薄膜，并使用交流电流感应磁化振荡技术测量有效磁场。基于 Pt 厚度依赖性，垂直于磁化方向和电流方向的横向有效场类似于 Rashba 效应，而平行于电流方向的纵向场类似于自旋霍尔效应。更重要的是，当Co厚度从0.6 nm变为0.9 nm时，横向和纵向场对Co层的敏感性急剧增加。层厚度的敏感性表明每层电流密度的相对电流分布对于在 Pt/Co/Al2O 和其他类似薄膜中达成广泛争议的自旋轨道强度达成共识的重要性。
We investigated the strength of the spin orbit interaction induced effective magnetic fields originating from two distinct mechanisms of different symmetry in Pt/Co/AlO trilayer films with varying Pt and Co thicknesses. Films are deposited by RF magnetron sputtering and effective magnetic fields are measured using an AC current induced magnetization oscillation technique. Based on the Pt thickness dependence, a transverse effective field perpendicular to both magnetization and current directions resembled Rashba effect while a longitudinal field parallel to the current direction was resembled to the spin Hall effect. More overwhelming is the sensitivity of the transverse and longitudinal fields to the Co layer which drastically increased when the Co thickness was changed from 0.6 to 0.9 nm. The sensitivity of the layer thickness indicates the importance of relative current distribution of the current density per layer in achieving a consensus of the widely controversial spin orbit strength in Pt/Co/AlO and other similar films.