Cheng Yang, Cogulu Egecan, Resnick Rachel D, Michel Justin J, Statuto Nahuel N, Kent Andrew D, Yang Fengyuan
Department of Physics, The Ohio State University, Columbus, OH, 43210, USA.
Department of Electrical and Computer Engineering, and Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA.
Nat Commun. 2022 Jun 27;13(1):3659. doi: 10.1038/s41467-022-31451-9.
Electrical switching of antiferromagnets is an exciting recent development in spintronics, which promises active antiferromagnetic devices with high speed and low energy cost. In this emerging field, there is an active debate about the mechanisms of current-driven switching of antiferromagnets. For heavy-metal/ferromagnet systems, harmonic characterization is a powerful tool to quantify current-induced spin-orbit torques and spin Seebeck effect and elucidate current-induced switching. However, harmonic measurement of spin-orbit torques has never been verified in antiferromagnetic heterostructures. Here, we report harmonic measurements in Pt/α-FeO bilayers, which are explained by our modeling of higher-order harmonic voltages. As compared with ferromagnetic heterostructures where all current-induced effects appear in the second harmonic signals, the damping-like torque and thermally-induced magnetoelastic effect contributions in Pt/α-FeO emerge in the third harmonic voltage. Our results provide a new path to probe the current-induced magnetization dynamics in antiferromagnets, promoting the application of antiferromagnetic spintronic devices.
反铁磁体的电开关是自旋电子学领域近期一项令人兴奋的进展，有望实现高速且低能耗的有源反铁磁器件。在这个新兴领域，关于反铁磁体电流驱动开关机制存在着激烈的争论。对于重金属/铁磁体系统，谐波表征是量化电流诱导的自旋轨道扭矩和自旋塞贝克效应以及阐明电流诱导开关的有力工具。然而，自旋轨道扭矩的谐波测量从未在反铁磁异质结构中得到验证。在此，我们报告了在Pt/α-FeO双层中的谐波测量结果，这些结果由我们对高阶谐波电压的建模得以解释。与铁磁异质结构中所有电流诱导效应都出现在二次谐波信号中不同，Pt/α-FeO中类似阻尼的扭矩和热诱导磁弹效应贡献出现在三次谐波电压中。我们的结果为探测反铁磁体中电流诱导的磁化动力学提供了一条新途径，推动了反铁磁自旋电子器件的应用。
