Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface
Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface
复制标题
准一维铁磁体-石墨烯界面处的动态自旋注入
DOI：
10.1063/1.4906578
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发表时间：
2014
影响因子：
4
通讯作者：
B. Ozyilmaz
中科院分区：
文献类型：
--
作者：
S. Singh;A. Ahmadi;C. Cherian;E. Mucciolo;E. Barco;B. Ozyilmaz
我们研究了从三维铁磁体到二维单层石墨烯的动态自旋注入。对埋在共面波导中心线下方的铁磁体/石墨烯条带的比较铁磁共振（FMR）研究表明，当石墨烯层远离铁磁体条带横向突出时，FMR线宽展宽最大，这表明自旋电流被注入石墨烯区域远离正被激发的铁磁体下方的区域。我们的研究结果证实，所观察到的阻尼确实是动态自旋注入的签名，其中纯自旋电流从铁磁体的旋进磁化被泵入单层石墨烯。观察到的自旋泵浦效率很难与根据标准自旋泵浦理论和石墨烯的特性所预期的自旋回流相一致，并且构成了二维结构中自旋泵浦的谜团。
We present a study of dynamical spin injection from a three-dimensional ferromagnet into two-dimensional single-layer graphene. Comparative ferromagnetic resonance (FMR) studies of ferromagnet/graphene strips buried underneath the central line of a coplanar waveguide show that the FMR linewidth broadening is the largest when the graphene layer protrudes laterally away from the ferromagnetic strip, indicating that the spin current is injected into the graphene areas away from the area directly underneath the ferromagnet being excited. Our results confirm that the observed damping is indeed a signature of dynamical spin injection, wherein a pure spin current is pumped into the single-layer graphene from the precessing magnetization of the ferromagnet. The observed spin pumping efficiency is difficult to reconcile with the expected backflow of spins according to the standard spin pumping theory and the characteristics of graphene, and constitutes an enigma for spin pumping in two-dimensional structures.