形状各向异性对垂直磁隧道结磁化动态的影响  

Effect of Shape Anisotropy on Magnetization Dynamics in Perpendicular Magnetic Tunnel Junctions

作　　者：刘斌[1] 刘喆颉 杨毅彪[1] 刘欣[1] 

机构地区：[1]太原理工大学物理与光电工程学院新型传感器与智能控制教育部与山西省重点实验室,太原030024 [2]新加坡国立大学电气与计算机工程系,新加坡117583

出　　处：《微纳电子技术》2015年第3期157-161,203,共6页Micronanoelectronic Technology

基　　金：国家自然科学基金资助项目(61274089);山西省国际合作项目(2014081029-2)

摘　　要：纳米磁性结构内磁矩翻转动态特性对于磁存储以及自旋电子学的研究具有十分重要的意义。基于Landau-Lifshitz-Gilbert(LLG)方程,研究了垂直磁各向异性(PMA)磁隧道结(MTJ)的自由层尺寸及磁矩倾角对磁矩翻转动力学特性的影响。具体讨论了宏自旋(Macrospin)模型中自由层的形状和尺寸对磁矩翻转特性的影响,给出了自由层磁矩翻转时间与阈值电流密度随自由层长度、厚度变化的特征。同时也分析了自由层磁矩倾角对磁矩翻转时间及阈值电流密度的影响。结果表明,在垂直MTJ结构中,小的磁矩倾角及合适的自由层长厚比可以大幅度地缩短磁矩翻转时间及减小所需阈值电流密度。Magnetization reversal dynamics in the magnetic nano-structures is of important signi- ficance for the researches of magnetic recording and spintronics. Based on the Landau-Lifshitz- Gilbert （LLG） equation, the effects of the free layer dimensions of the perpendicular magnetic anisotropy （PMA） magnetic tunnel junction （MTJ） and magnetization tilt angle on the dynamic characteristics of the magnetization reversal were studied. The influences of the free layer shape and sizes on the magnetization reversal characteristics in the Macrospin model were particularly discussed, and the change characteristics of the magnetization switching time of the free layer and threshold current density as a function of the length and thickness of the free layer were presen- ted. Meanwhile, the influences of the magnetization tilt angle of the free layer on the magnetiza- tion switching time and threshold current density were analyzed. The results show that the small magnetization tilt angle and appropriate aspect ratio of the free layer can significantly reduce the magnetization switching time and required threshold current density in the perpendicular MTJ structure.

关 键 词：宏自旋 垂直磁各向异性(PMA) 磁隧道结(MTJ) 磁矩翻转 自由层 

分 类 号：TB383[一般工业技术—材料科学与工程] O482.54[理学—固体物理]