Antidamping torques from simultaneous resonances in ferromagnet-topological insulator-ferromagnet heterostructures
Antidamping torques from simultaneous resonances in ferromagnet-topological insulator-ferromagnet heterostructures
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DOI：
10.1016/j.jmmm.2018.10.109
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发表时间：
2019-03-01
影响因子：
2.7
通讯作者：
van der Laan, G.
中科院分区：
文献类型：
--
作者：
Baker, A. A.;Figueroa, A., I;van der Laan, G.
利用铁磁共振（FMR）方法研究了拓扑绝缘体（TI）Bi 2Se 3层上铁磁薄膜的磁动力学特性。TI吸引了整个物理学界的广泛关注，因为它们具有无耗散载流子输运的潜力，极高的自旋轨道扭矩，并且是新颖量子效应的宿主。为了研究铁磁（FM）层之间的耦合，矢量网络分析仪（VNA）-FMR测量的谐振线宽作为偏置场角的函数进行。通过使两个FM层的共振非常接近，可以观察到导致线宽变窄的反阻尼扭矩，这是自旋泵浦的一个特征。X射线检测的铁磁共振（XFMR）的元素，因此层特定的技术被用来规避的困难，获得准确的拟合到两个重叠的共振非常接近。我们的研究结果证实，整个TI的相互作用是一个动态的交换介导的自旋泵，而不是一个自耦合的表面状态或类似的，更非常规的机制。
We studied the magnetodynamics of ferromagnetic films coupling across a topological insulator (TI) Bi2Se3 layer using ferromagnetic resonance (FMR). TIs have attracted much attention across the physics community as they hold the potential for dissipationless carrier transport, extremely high spin-orbit torques, and are host to novel quantum effects. To investigate the coupling between the ferromagnetic (FM) layers, vector network analyzer (VNA)-FMR measurements of the resonance linewidth were performed as a function of bias field angle. By bringing the resonances of the two FM layers into close proximity, it was possible to observe antidamping torques that lead to a narrowing of linewidth, a characteristic of spin pumping. The element- and hence layer-specific technique of X-ray detected ferromagnetic resonance (XFMR) was used to circumvent the difficulty of obtaining accurate fits to the two overlapping resonances in close proximity. Our results confirm that the interaction across the TI is a dynamic exchange mediated by spin pumping, as opposed to a self-coupling of the surface state or similar, more unconventional mechanisms.