Simple Analysis for Frequency Increase in Spin Torque Oscillation
Simple Analysis for Frequency Increase in Spin Torque Oscillation
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自旋力矩振荡频率增加的简单分析
DOI：
10.1109/tmag.2012.2201700
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and M.Mizuguchi
中科院分区：
文献类型：
--
作者：
C.Mitsumata;S.Tomita;T.Seki;and M.Mizuguchi
利用Landau-Lifshitz-吉尔伯特（LLG）方程研究了磁共振引起的自旋力矩振荡（STO）。具有宏自旋的LLG方程的解析式描述了涉及振荡频率信息的自旋状态。LLG方程可以转化为强迫振动方程。所得到的方程包括STO的频率、有效吉尔伯特阻尼因子和注入的自旋电流。我们表明，有效的吉尔伯特阻尼是由一个线性函数的自旋电流。相反，STO的频率不受注入的自旋电流的影响。然而，自旋电流的时间依赖性变化，例如，脉动的自旋电流可能增加STO的频率。
The spin torque oscillation (STO) due to magnetic resonance is investigated in term of the Landau-Lifshitz-Gilbert (LLG) equation. An analytic formula of the LLG equation with macro-spins describes a spin state that involves information of an oscillation frequency. The LLG equation can be transformed into an equation of a forced oscillation. The obtained equation includes a frequency of STO, an effective Gilbert damping factor, and an injected spin current. We show that the effective Gilbert damping is given by a linear function of the spin current. Contrastingly, the frequency of STO is not affected by the injected spin current. However, the time-dependent variation of the spin current, e.g., the pulsated spin current, possibly increases the frequency of STO.