Non-Markovian Magnetization Dynamics for Uniaxial Nanomagnets
Non-Markovian Magnetization Dynamics for Uniaxial Nanomagnets
复制标题
单轴纳米磁体的非马尔可夫磁化动力学
DOI：
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发表时间：
2015
影响因子：
2.1
通讯作者：
S. Nicolis
中科院分区：
文献类型：
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作者：
P. Thibaudeau;J. Tranchida;S. Nicolis
提出了一种描述纳米磁体磁化时间演化的随机方法，该方法通过改变噪声强度，在Landau-Lifshitz-Gilbert近似和Landau-Lifshitz-Bloch近似之间进行插值。它的有限自相关时间，即当它可以被描述为彩色，而不是白色时，也被考虑在内，并对磁化响应规模的后果进行了研究。通过引入一种合适的截断格式，证明了磁化矩的层次是可以封闭的，并通过对矩方程的直接数值解，与相应的彩色随机朗之万方程的数值解的平均值进行了比较，验证了截断格式的有效性。这种比较是在受外部均匀磁场和内部单点单轴各向异性影响的磁系统上进行的。
A stochastic approach for the description of the time evolution of the magnetization of nanomagnets is proposed, that interpolates between the Landau-Lifshitz-Gilbert and the Landau-Lifshitz-Bloch approximations, by varying the strength of the noise. Its finite autocorrelation time, i.e., when it may be described as colored, rather than white, is also taken into account, and the consequences on the scale of the response of the magnetization are investigated. It is shown that the hierarchy for the moments of the magnetization can be closed, by introducing a suitable truncation scheme, whose validity is tested by direct numerical solution of the moment equations and compared with the averages obtained from a numerical solution of the corresponding colored stochastic Langevin equation. This comparison is performed on magnetic systems subject to both an external uniform magnetic field and an internal one-site uniaxial anisotropy.