Quantifying interface and bulk contributions to spin-orbit torque in magnetic bilayers
Quantifying interface and bulk contributions to spin-orbit torque in magnetic bilayers
复制标题
DOI：
10.1038/ncomms4042
复制
发表时间：
2014-01-01
影响因子：
16.6
通讯作者：
Xiao, John Q.
中科院分区：
文献类型：
--
作者：
Fan, Xin;Celik, Halise;Xiao, John Q.
自旋轨道相互作用驱动的现象，如自旋霍尔和Rashba效应在铁磁/重金属双层，使有效的操纵磁化通过电流。然而，自旋轨道相互作用驱动的现象的基本机制仍然没有解决。在这里，我们开发了一个敏感的自旋-轨道扭矩磁强计的磁光克尔效应的基础上，测量的自旋-轨道扭矩矢量钴铁硼/铂双层膜在很宽的厚度范围。我们观察到的Slonczewski扭矩与铁磁层的厚度成反比，和类场扭矩有一个阈值效应，只有当铁磁层薄于1 nm时才出现。通过在界面处附加铜插入层的厚度依赖性研究，我们得出结论，该系统中自旋轨道相互作用驱动现象的主导机制是自旋霍尔效应。然而，也有一个明显的界面贡献，这可能是因为Rashba效应。
Spin-orbit interaction-driven phenomena such as the spin Hall and Rashba effect in ferromagnetic/heavy metal bilayers enables efficient manipulation of the magnetization via electric current. However, the underlying mechanism for the spin-orbit interaction-driven phenomena remains unsettled. Here we develop a sensitive spin-orbit torque magnetometer based on the magneto-optic Kerr effect that measures the spin-orbit torque vectors for cobalt iron boron/platinum bilayers over a wide thickness range. We observe that the Slonczewski-like torque inversely scales with the ferromagnet thickness, and the field-like torque has a threshold effect that appears only when the ferromagnetic layer is thinner than 1 nm. Through a thickness-dependence study with an additional copper insertion layer at the interface, we conclude that the dominant mechanism for the spin-orbit interaction-driven phenomena in this system is the spin Hall effect. However, there is also a distinct interface contribution, which may be because of the Rashba effect.