基于非共线自旋源的自旋轨道力矩驱动磁畴壁运动  

Magnetic domain wall motion driven by spin-orbit torque based on non-collinear spin source

作　　者：赵阳 任传童 孟德全 王瑞龙[1] 罗为[2] 张悦[2] 梁世恒 Yang Zhao;Chuantong Ren;Dequan Meng;Ruilong Wang;Wei Luo;Yue Zhang;Shiheng Liang(Faculty of Physics,Hubei University,Wuhan 430062,China;School of Optics and Electronic Information,Huazhong University of Science and Technology,Wuhan 430074,China;Hubei Key Laboratory of Ferroelectric Materials and Devices,Wuhan 430062,China)

机构地区：[1]湖北大学物理学院,武汉430062 [2]华中科技大学光学与电子信息学院,武汉430074 [3]铁电压电材料与器件湖北省重点实验室,武汉430062

出　　处：《科学通报》2023年第5期524-531,共8页Chinese Science Bulletin

基　　金：国家重点研发计划(2022YFE0103300);国家自然科学基金(11904088);湖北省杰出青年科学基金(2022CFA088)资助。

摘　　要：通过电学有效驱动磁畴壁运动是自旋电子学领域的重要研究内容之一,其中零磁场下基于自旋轨道力矩效应驱动磁矩翻转是一种重要的磁畴壁运动调控方式.为了进一步实现低功耗、高速度、高效率的磁畴壁运动,本文研究了非共线自旋源所产生的区别于传统型自旋轨道力矩对磁畴的驱动行为.我们利用微磁学模拟研究了自旋流中类Rashba的Sy、类Dresselhaus的Sx和垂直于膜面的S_(z)三种自旋极化下自旋轨道力矩驱动磁畴壁运动,阐明了对布洛赫畴壁(Bloch wall)、奈尔畴壁(Néel wall)和头对头畴壁(head-to-head wall)的驱动及畴壁性质的影响,探究了Dzyaloshinskii-Moriya相互作用下磁畴壁运动中倾斜角的影响.本文对于理解基于非共线自旋源的自旋轨道力矩驱动磁畴壁运动具有一定意义,可为新型自旋电子器件的开发和应用提供物理基础.Recently,the current-induced motion of magnetic domain walls has attracted much attention.It enables electrical control of domain wall motion without the application of an external magnetic field and thus has potential applications in highperformance magnetic racetrack memories,among others.The effective control of domain wall motion under zero magnetic field is one of the important topics in spintronics research.Current-driven magnetization switching via the spinorbit torque effect is an important approach to realizing the field-free domain wall motion.The traditional research structure of spin-orbit torques is non-magnetic material/magnetic material(NM/FM)heterogeneous films,in which non-magnetic materials are used as the spin source layer to generate and provide spin current through charge-to-spin current conversion.Common non-magnetic materials mainly include heavy metals,such as Pt,β-Ta andβ-W.However,in the system with heavy metals as spin sources,the conventional spin Hall effect requires the charge current,spin current and spin polarization directions to be perpendicular to each other,so it is necessary to apply an in-plane auxiliary magnetic field to break the symmetry,especially when driving the perpendicular magnetic moment switching,which increases extra power consumption and is not conducive to practical applications.Recently,it has been found that the spin current generated by the charge current in the outer semimetal WTe2is spin polarized in the z-direction.It has a unique in-plane symmetry breaking property,where the damping-like torque can contribute more to the domain wall motion of a ferromagnetic layer with perpendicular magnetic anisotropy.Moreover,a unique Rashba-like spin polarization has recently emerged in the noncollinear magnetic structure Mn3GaN.A charge current is applied in the x-direction to generate a spin current in the z-direction,with spin polarization along the x-direction.The spin polarization along the x-direction produces damping-like torque(τx,DL)and field-like torque(τ

关 键 词：自旋电子学 自旋轨道力矩 磁畴壁运动 电荷-自旋转换 

分 类 号：O469[理学—凝聚态物理]