Xie Xuejie, Zhao Xiaonan, Dong Yanan, Qu Xianlin, Zheng Kun, Han Xiaodong, Han Xiang, Fan Yibo, Bai Lihui, Chen Yanxue, Dai Youyong, Tian Yufeng, Yan Shishen
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, China.
Beijing Key Lab of Microstructure and Property of Solids, Institute of Microstructure and Properties of Advanced Material, Beijing University of Technology, Beijing, China.
Nat Commun. 2021 Apr 30;12(1):2473. doi: 10.1038/s41467-021-22819-4.
Programmable magnetic field-free manipulation of perpendicular magnetization switching is essential for the development of ultralow-power spintronic devices. However, the magnetization in a centrosymmetric single-layer ferromagnetic film cannot be switched directly by passing an electrical current in itself. Here, we demonstrate a repeatable bulk spin-orbit torque (SOT) switching of the perpendicularly magnetized CoPt alloy single-layer films by introducing a composition gradient in the thickness direction to break the inversion symmetry. Experimental results reveal that the bulk SOT-induced effective field on the domain walls leads to the domain walls motion and magnetization switching. Moreover, magnetic field-free perpendicular magnetization switching caused by SOT and its switching polarity (clockwise or counterclockwise) can be reversibly controlled in the IrMn/Co/Ru/CoPt heterojunctions based on the exchange bias and interlayer exchange coupling. This unique composition gradient approach accompanied with electrically controllable SOT magnetization switching provides a promising strategy to access energy-efficient control of memory and logic devices.
可编程的无磁场垂直磁化翻转操控对于超低功耗自旋电子器件的发展至关重要。然而，中心对称单层铁磁薄膜中的磁化不能通过自身通电流直接翻转。在此，我们通过在厚度方向引入成分梯度以打破空间反演对称性，演示了垂直磁化的CoPt合金单层薄膜的可重复体自旋轨道矩（SOT）翻转。实验结果表明，体SOT在畴壁上诱导的有效场导致畴壁运动和磁化翻转。此外，基于交换偏置和层间交换耦合，在IrMn/Co/Ru/CoPt异质结中，由SOT引起的无磁场垂直磁化翻转及其翻转极性（顺时针或逆时针）可以被可逆地控制。这种独特的成分梯度方法与电可控的SOT磁化翻转相结合，为实现对存储器和逻辑器件的节能控制提供了一种有前景的策略。
