重金属层/铁磁层界面反演对称性破缺诱导的垂直磁矩零场翻转  

Field-free Switching of Perpendicular Magnetization Induced by Inversion Symmetry Breaking at the Heavy-metal/Merromagnet Interface

作　　者：王佳才 郭晓庆 吴敏[1,2] 薛海斌 WANG Jiacai;GUO Xiaoqing;WU Min;XUE Haibin(College of Physics,Taiyuan University of Technology,Taiyuan 030024,China;Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学物理学院,山西太原030024 [2]太原理工大学新材料界面科学与工程教育部重点实验室,山西太原030024

出　　处：《山西大学学报（自然科学版）》2024年第5期1036-1047,共12页Journal of Shanxi University(Natural Science Edition)

基　　金：山西省应用基础研究计划项目(20210302123184,201601D011015);山西省高等学校优秀青年学术带头人支持计划(163220120-S)。

摘　　要：本文基于宏自旋模型,研究了重金属层/铁磁层,即L11相CuPt/CoPt界面反演对称性破缺诱导的面外类场矩对铁磁层垂直磁矩零场翻转特性的影响。研究结果表明:对于存在反演对称性破缺的L11相CuPt/CoPt界面,当沿着其重金属层的高对称轴通入一个合适的短脉冲电流时,虽然界面反演对称性破缺诱导的面外类场矩,即3 m力矩在x-y平面内为零,但是,利用磁矩在x-y平面上下产生的非稳定振荡效应同样可以实现垂直磁矩的确定性零场翻转。此外,当该面外类场矩较大时,其可以增大短脉冲电流的长度选择范围,并进一步减小磁矩稳定翻转的阈值电流。上述结果为实现零场的自旋轨道矩磁随机存储器提供了一个可选择的理论方案。In this paper,the influence of the out-of-plane field-like torque induced by the interfacial inversion symmetry breaking in the heavy-metal/ferromagnet(the L11 phase CuPt/CoPt)bilayer on the characteristics of field-free perpendicular magnetization switching in the ferromagnetic layer is studied based on the macro-spin model.It is demonstrated that in the L11 phase CuPt/CoPt bilayer with the inversion symmetry breaking,though the induced out-of-plane field-like torque,namely,the 3 m torque is quenched in the x-y plane,the field-free perpendicular magnetization switching can also be observed through the unsteady oscillating effect of the magnetization between above the x-y plane and below the one,when an appropriate short pulsed electric current is to be applied along the high symmetry axis of the heavy metal layer.Moreover,when the induced out-of-plane field-like torque is large enough,it can increase the selection range of short pulsed current length and further reduce the threshold current density of the steady magnetization switching.These results suggest an alternative theoretical scheme for the realization of field-free perpendicular magnetization switching of spin-orbit torque-magnetic random access memory.

关 键 词：宏自旋模型 自旋轨道矩 磁随机存储器 

分 类 号：O469[理学—凝聚态物理]