Brownian dynamics approach to interacting magnetic moments
Brownian dynamics approach to interacting magnetic moments
复制标题
相互作用磁矩的布朗动力学方法
DOI：
10.1016/s0304-8853(03)00452-9
复制
发表时间：
2002
影响因子：
2.7
通讯作者：
J. González
中科院分区：
文献类型：
--
作者：
O. Chubykalo;R. Smirnov;M. Wongsam;R. Chantrell;U. Nowak;J. González
讨论了如何在磁系统的运动方程中引入热波动的问题。利用波动耗散定理的方法计算了波动场和加性波动力矩（力）表示的噪声性质。与先前的计算相反，我们考虑相互作用磁矩系统的一般情况。我们表明，相互作用不会导致场表示中热波动的任何相关性，并且可以在最一般的情况下使用相同的广泛使用的公式。进一步证明了在涨落耗散定理成立的平衡点附近，场和加性转矩（力）的表示一致，而在远离平衡点时则不同。本文还表明，噪声的不相关特性是由Landau-Lifshitz（或Gilbert）阻尼的形式引起的，在不同的阻尼形式下，正态模态分析是合适的。
The question of how to introduce thermal fluctuations in the equation of motion of a magnetic system is addressed. Using the approach of the fluctuation-dissipation theorem we calculate the properties of the noise for both, the fluctuating field and the additive fluctuating torque (force) representation. In contrast to earlier calculations we consider the general case of a system of interacting magnetic moments. We show that the interactions do not result in any correlations of thermal fluctuations in the field representation and that the same widely used formula can be used in the most general case. We further prove that close to the equilibrium where the fluctuation-dissipation theorem is valid, both, field and additive torque (force) representations coincide, being different far away from it. We also show that the uncorrelated character of the noise is due to the form of the Landau-Lifshitz (or Gilbert) damping and under different damping formalisms, the normal mode analysis is proper.