论文标题
由下胸微波脉冲驱动的磁性纳米颗粒的热辅助磁化逆转
Thermally assisted magnetization reversal of a magnetic nanoparticle driven by a down-chirp microwave field pulse
论文作者
论文摘要
已经表明，单域磁性纳米颗粒可以通过零温度极限的线性下矫正微波场脉冲（DCMWP）有效切换。但是，实际上，有限温度无处不在。在这里，我们研究了有限温度对基于随机Landau-Lifshitz-Gilbert方程的DCMWP诱导的磁化逆转的影响。发现DCMWP的三个控制参数中的任何一个，即振幅，CHIRP速率或初始频率，随着温度的增加而降低，而其他两个则固定。逆转可能发生的最大温度随着系统尺寸的扩大而增加。这些现象与以下事实有关：事实是，各向异性诱导的能屏障随系统体积的增加而增加，并且有效的磁化强度随温度而降低。我们还提供了一组最佳参数，以实现我们的建议。这些发现可能提供了一种以广泛的工作温度实现低成本和快速磁化逆转的方法。
It has been shown that a single-domain magnetic nanoparticle can be effectively switched by a linear down-chirp microwave field pulse (DCMWP) in zero temperature limit. However, finite temperature is ubiquitous in practice. Here, we study the effect of finite temperature on the DCMWP-induced magnetization reversal based on the stochastic Landau-Lifshitz-Gilbert equation. It is found that any one of the three controlling parameters of a DCMWP, i.e. the amplitude, chirp rate, or initial frequency, decreases with increasing temperature while the other two are fixed. The maximal temperature at which the reversal can happen increases with enlarging the system size. These phenomena are related to the facts that the energy barrier induced by anisotropy increases with the system volume, and the effective magnetization decreases with temperature. We also provide a set of optimal parameters for practical realization of our proposal. These findings may provide a way to realize low-cost and fast magnetization reversal with a wide operating temperature.
