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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。
The magnetic moment reversal dynamics in the nano-magnetic structure is of great significance for the study of magnetic storage and spintronics. Based on the Landau-Lifshitz-Gilbert (LLG) equation, the influence of the free layer size and magnetic moment dip on the magnetic moment reversal dynamics was investigated for the perpendicular magnetic anisotropy (PMA) magnetic tunnel junction (MTJ). The influence of the shape and size of the free layer in the Macrospin model on the magnetic moment reversal characteristics is discussed in detail. The characteristics of the change of the magnetic moment reversal time and the threshold current density with the free layer length and thickness are given. At the same time, the influence of the magnetic dip angle of the free layer on the magnetic moment overturning time and the threshold current density is also analyzed. The results show that in the vertical MTJ structure, the small magnetic moment dip and the appropriate aspect ratio of the free layer can shorten the magnetic moment reversal time and decrease the required threshold current density.