Phase-resolved x-ray ferromagnetic resonance measurements of spin pumping in spin valve structures
Phase-resolved x-ray ferromagnetic resonance measurements of spin pumping in spin valve structures
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DOI：
10.1103/physrevb.87.180403
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发表时间：
2013-05-21
影响因子：
3.7
通讯作者：
Hicken, R. J.
中科院分区：
文献类型：
--
作者：
Marcham, M. K.;Shelford, L. R.;Hicken, R. J.
元素特定的相位分辨x射线铁磁共振（FMR）被用于研究大面积Co 50 Fe 50（3）/Cu（6）/Ni 80 Fe 20（5）（厚度以纳米计）自旋阀结构中的自旋泵浦，从而可以忽略标准磁输运实验中使用的纳米柱的典型边缘效应。Co 50 Fe 50固定层的旋进相被记录为在Ni 80 Fe 20自由层中诱导的FMR。固定层相位的场依赖性包含由于自旋泵浦的自旋转移矩（STT）耦合的清晰签名。拟合相位延迟产生自旋混合电导，控制所有自旋转移现象的量。STT耦合被破坏的Ta插入到中间的Cu层。
Element-specific phase-resolved x-ray ferromagnetic resonance (FMR) was used to study spin pumping within Co50Fe50(3)/Cu(6)/Ni80Fe20(5) (thicknesses in nanometers) spin valve structures with large areas, so that edge effects typical of nanopillars used in standard magnetotransport experiments could be neglected. The phase of precession of the Co50Fe50 fixed layer was recorded as FMR was induced in the Ni80Fe20 free layer. The field dependence of the fixed layer phase contains a clear signature of spin transfer torque (STT) coupling due to spin pumping. Fitting the phase delay yields the spin-mixing conductance, the quantity that controls all spin transfer phenomena. The STT coupling is destroyed by insertion of Ta into the middle of the Cu layer.