Temperature dependence of spin-orbit torques in Pt/Co/Pt multilayers
Temperature dependence of spin-orbit torques in Pt/Co/Pt multilayers
复制标题
Pt/Co/Pt 多层膜中自旋轨道扭矩的温度依赖性
DOI：
10.1088/1361-6463/aaa7c8
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Xue Desheng
中科院分区：
文献类型：
--
作者：
Chen Shiwei;Li Dong;Cui Baoshan;Xi Li;Si Mingsu;Yang Dezheng;Xue Desheng
通过测量谐波霍尔电压，研究了垂直磁化Pt (1 nm)/Co (0.8 nm)/Pt （5 nm）异质结中电流诱导的自旋轨道转矩。由于Pt/Co/Pt界面相似，Rashba效应产生的自旋轨道转矩减小，但由于Pt厚度不对称，自旋霍尔效应的贡献仍然存在。当温度从50 K增加到300 K时，由自旋-轨道力矩引起的有效场的两个正交分量显示出相反的温度依赖性：类场项（横向有效场）从2.3减小到2.1(10−6 Oe (A cm−2)−1)，而类阻尼项（纵向有效场）从3.7增加到4.8（10−6 Oe (A cm−2)−1）。我们注意到，在相似的Pt/Co界面中，类阻尼项通常比类场项小，但却是类场项的两倍大。结果表明，在300 K时，类阻尼自旋轨道转矩的效率为0.15。在Pt/Co/Pt异质结中，这种温度相关的类阻尼项可以有效地降低开关电流密度，在300 K时开关电流密度为2.30× 10 6 a cm−2，为进一步改善和理解自旋霍尔效应引起的自旋轨道转矩提供了机会。
We studied the current-induced spin–orbit torques in a perpendicularly magnetized Pt (1 nm)/Co (0.8 nm)/Pt (5 nm) heterojunction by harmonic Hall voltage measurements. Owing to similar Pt/Co/Pt interfaces, the spin–orbit torques originated from the Rashba effect are reduced, but the contribution from the spin Hall effect is still retained because of asymmetrical Pt thicknesses. When the temperature increases from 50 to 300 K, two orthogonal components of the effective field, induced by spin–orbit torques, reveal opposite temperature dependencies: the field-like term (transverse effective field) decreases from 2.3 to 2.1 (10− 6 Oe (A cm− 2)− 1), whereas the damping-like term (longitudinal effective field) increases from 3.7 to 4.8 (10− 6 Oe (A cm− 2)− 1). It is noticed that the damping-like term, usually smaller than the field-like term in the similar Pt/Co interfaces, is twice as large as the field-like term. As a result, the damping-like spin–orbit torque reaches an efficiency of 0.15 at 300 K. Such a temperature-dependent damping-like term in a Pt/Co/Pt heterojunction can efficiently reduce the switching current density which is 2.30× 10 6 A cm− 2 at 300 K, providing an opportunity to further improve and understand spin–orbit torques induced by spin Hall effect.