Origin of the magnetic field enhancement of the spin signal in metallic nonlocal spin transport devices
Origin of the magnetic field enhancement of the spin signal in metallic nonlocal spin transport devices
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DOI：
10.1103/physrevb.104.014423
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发表时间：
2021-07
影响因子：
3.7
通讯作者：
A. J. Wright;M. Erickson;D. Bromley;P. Crowell;C. Leighton;L. O’Brien
中科院分区：
文献类型：
--
作者：
A. J. Wright;M. Erickson;D. Bromley;P. Crowell;C. Leighton;L. O’Brien
非局域自旋阀(NLSV)能够对自旋输运进行明确的研究，因为它能够隔离纯的自旋流。NLSV工作的一个关键原理是，在面内磁场(高于铁磁接触饱和场)的作用下，‘自旋信号’是不变的。然而，对于NLSV中的某些铁磁/正常金属配对，自旋信号发生了意想不到的场增强，这是一个到目前为止用现有模型很难解决的挑战。通过将所提取的自旋输运参数与材料、温度和场的依赖关系相关联，在这项工作中，我们确定了磁杂质散射的场猝灭是这种效应的来源，我们的结果与依赖于场的Kondo理论很好地一致。除了解决这个长期存在的谜团外，我们的发现还突显了对自旋输运参数潜在的系统性低估。通过确定标记场和温度的依赖关系，我们在这里提供了一种相对简单的方法来分离和量化这种额外的驰豫机制。
The nonlocal spin valve (NLSV) enables unambiguous study of spin transport, owing to its ability to isolate pure spin currents. A key principle of NLSV operation is that the ``spin signal'' is invariant under application of in-plane magnetic fields (above the ferromagnetic contact saturation field). Yet, for certain ferromagnet/normal metal pairings in NLSVs, an unexpected field enhancement of the spin signal occurs, presenting a challenge that has, thus far, been difficult to resolve with existing models. By correlating the extracted spin transport parameters with material, temperature, and field dependencies, in this work we identify field quenching of magnetic impurity scattering as the origin of this effect, confirmed by excellent agreement between our results and field-dependent Kondo theory. In addition to addressing this long-standing mystery, our findings highlight a potential systematic underestimation of spin transport parameters. By identifying signature field and temperature dependencies, we provide here a relatively simple means to isolate and quantify this additional relaxation mechanism.