摘要
以磁隧道结/重金属层组成的三端口磁隧道结为理论模型,通过对包含自旋转移矩和自旋轨道矩的Landau-Lifshitz-Gilbert(LLG)方程做线性化稳定性分析,研究了自旋轨道矩协助自旋转移矩驱动的磁化强度翻转.发现在自旋轨道矩协助下,磁矩的翻转时间极大减小,翻转时间随自旋轨道矩电流密度的增大而减小,且自旋转移矩和自旋轨道矩的结合可实现零磁场的磁化翻转.另外,相比自旋轨道矩的类阻尼项,类场项在磁化强度的翻转中起着主导作用,且自旋轨道矩类场项的出现也可以减小磁化强度的翻转时间,磁化强度翻转时间随自旋轨道矩类场项强度的增大而减小.
As the data writing scheme of magnetization reversal driven by spin-transfer torque can overcome the shortcomings of traditional magnetic-field writing mechanism,it has become a mainstream way of implementing information writing in magnetic random access memory.However,the explosive growth of information shows higher requirements for data storage and information processing,thus magnetic random access memories based on spin-transfer torque data writing method pose several issues,including barrier reliability and limited storage speed.Recent experimental studies have shown that the spin-orbit torque through the spin Hall effect or Rashba effect in heavy-metal/ferromagnetic bilayer structures has the potential advantages in overcoming these limitations.They can also be used to drive magnetization to achieve rapid reversal.Especially,the three-terminal magnetic tunnel junction separates data reading from writing current.It has the advantages of faster writing speed and better stability and thus becomes the most promising magnetic storage technique at present.The magnetization reversal driven by spin-orbit-assisted spin-transfer torque in a three-terminal magnetic tunnel junction is studied theoretically in this work.By linearizing the Landau-Lifshitz-Gilbert equation with the additional spin-transfer torque term and spin-orbit torque term in the spherical coordinates,two coupled differential equations and the new equilibrium directions are obtained.With the stability analysis of the new equilibrium directions,the phase diagrams defined in parameter space spanned by the current densities of spin-transfer and spin-orbit torques are established.There are several magnetic states in the phase diagrams,including quasi-parallel stable states,quasi-antiparallel stable states,and bistable states.By adjusting the current density of the spin-transfer torque,the magnetization reversal between two stable states is realized.It is found that the magnetization reversal time is greatly reduced with the assisting of spin-orbit torque,
作者
王日兴
曾逸涵
赵婧莉
李连
肖运昌
Wang Ri-Xing;Zeng Yi-Han;Zhao Jing-Li;Li Lian;Xiao Yun-Chang(College of Computer and Electrical Engineering,Hunan University of Arts and Science,Changde 415000,China;Normal College,Hunan University of Arts and Science,Changde 415000,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第8期280-286,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11704120)
湖南省教育厅优秀青年项目(批准号:20B401)
湖南省教育厅一般项目(批准号:21C0509)资助的课题。
关键词
磁化翻转
自旋转移矩
自旋轨道矩
magnetization reversal
spin-transfer torque
spin-orbit torque
