Magnetization dynamics, gyromagnetic relation, and inertial effects
Magnetization dynamics, gyromagnetic relation, and inertial effects
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磁化动力学、旋磁关系和惯性效应
DOI：
10.1119/1.4709188
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发表时间：
2011
影响因子：
0.9
通讯作者：
M. Ciornei
中科院分区：
文献类型：
--
作者：
J. Wegrowe;M. Ciornei
旋磁关系--即角动量L→和磁化强度M→之间的比例关系--证明了铁磁体的磁性和惯性之间的密切联系。然而，磁偶极子的动力学中不存在惯性：朗道-利夫希茨方程、吉尔伯特方程和布洛赫方程只包含磁化强度对时间的一阶导数。为了研究这种矛盾的情况下，拉格朗日方法，最初提出的吉尔伯特，被重新审视保持任意非零的惯性张量。相应的物理图像是安培分子流假设的三维推广。得到了一个推广到惯性区的动力学方程。它示出了如何恢复通常的旋磁关系和著名的朗道-Lifshitz-吉尔伯特方程的动力学极限，即，时间尺度长于角的弛豫时间。
The gyromagnetic relation—that is, the proportionality between the angular momentum L→ and the magnetization M→—is evidence of the intimate connections between the magnetic properties and the inertial properties of ferromagnetic bodies. However, inertia is absent from the dynamics of a magnetic dipole: The Landau–Lifshitz equation, the Gilbert equation, and the Bloch equation contain only the first derivative of the magnetization with respect to time. In order to investigate this paradoxical situation, the Lagrangian approach, proposed originally by Gilbert, is revisited keeping an arbitrary nonzero inertia tensor. The corresponding physical picture is a generalization to three dimensions of Ampere’s hypothesis of molecular currents. A dynamic equation generalized to the inertial regime is obtained. It is shown how both the usual gyromagnetic relation and the well-known Landau–Lifshitz–Gilbert equation are recovered in the kinetic limit, that is, for time scales longer than the relaxation time of the angu...