We study magnetization switching in the dynamical regime for in-plane magnetized systems, useful for field-free spin-orbit torque switching devices. We derive a formula for the switching probability, characterized by the thermal stability factor, critical current density, and the linewidth of ferromagnetic resonance. The formula agrees well with numerical simulations based on the Landau-Lifshitz-Gilbert equation. To study the viability of the theory developed, the switching probability of an in-plane magnetized ferromagnet in three-terminal spin-orbit torque switching devices is measured. We find that the transition width of the switching probability versus current increases with decreasing pulse width. The shape of the probability density, the current derivative of the switching probability, changes with varying pulse width. These characteristics are in good agreement with the theory developed. From the analyses, we show that the dynamical and thermally activated switching regimes can be distinguished simply from the shape of the probability density. The formula therefore provides useful means to analyze the switching probability of two-terminal spin torque and three-terminal spin-orbit torque switching devices.

中文翻译：

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自旋转移矩驱动的动态切换机制中的磁化切换概率

我们研究了平面内磁化系统的动态状态下的磁化切换，这对于无场自旋轨道扭矩切换装置很有用。我们推导出开关概率的公式，以热稳定性因子、临界电流密度和铁磁共振线宽为特征。该公式与基于 Landau-Lifshitz-Gilbert 方程的数值模拟非常吻合。为了研究所开发理论的可行性，测量了平面内磁化铁磁体在三端自旋轨道扭矩切换装置中的切换概率。我们发现开关概率与电流的转换宽度随着脉冲宽度的减小而增加。概率密度的形状，即开关概率的电流导数，随着脉冲宽度的变化而变化。这些特征与所发展的理论非常吻合。从分析中，我们表明动态和热激活的切换机制可以简单地从概率密度的形状中区分出来。因此，该公式为分析两端自旋扭矩和三端自旋轨道扭矩切换装置的切换概率提供了有用的手段。