Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nat Mater. 2017 Mar;16(3):309-314. doi: 10.1038/nmat4812. Epub 2016 Nov 21.
The spin Hall effect in heavy metals converts charge current into pure spin current, which can be injected into an adjacent ferromagnet to exert a torque. This spin-orbit torque (SOT) has been widely used to manipulate the magnetization in metallic ferromagnets. In the case of magnetic insulators (MIs), although charge currents cannot flow, spin currents can propagate, but current-induced control of the magnetization in a MI has so far remained elusive. Here we demonstrate spin-current-induced switching of a perpendicularly magnetized thulium iron garnet film driven by charge current in a Pt overlayer. We estimate a relatively large spin-mixing conductance and damping-like SOT through spin Hall magnetoresistance and harmonic Hall measurements, respectively, indicating considerable spin transparency at the Pt/MI interface. We show that spin currents injected across this interface lead to deterministic magnetization reversal at low current densities, paving the road towards ultralow-dissipation spintronic devices based on MIs.
重金属中的自旋霍尔效应将电荷电流转换为纯自旋电流，该电流可注入到相邻的铁磁体中以产生扭矩。这种自旋轨道扭矩（SOT）已被广泛用于操纵金属铁磁体中的磁化。对于磁性绝缘体（MI），尽管不能有电荷电流流动，但自旋电流可以传播，但是到目前为止，电流感应对 MI 中磁化的控制仍然难以实现。在这里，我们演示了由 Pt 覆盖层中的电荷电流驱动的垂直磁化钬铁石榴石薄膜的自旋电流诱导切换。我们通过自旋霍尔磁电阻和谐波霍尔测量分别估计了较大的自旋混合电导率和阻尼型 SOT，表明在 Pt/MI 界面处具有相当大的自旋透明度。我们表明，注入该界面的自旋电流在低电流密度下导致确定的磁化反转，为基于 MI 的超低损耗自旋电子器件铺平了道路。
