Variational principle for magnetisation dynamics in a temperature gradient
Variational principle for magnetisation dynamics in a temperature gradient
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DOI：
10.1209/0295-5075/112/17006
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
S. Brechet;J. Ansermet
中科院分区：
文献类型：
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作者：
S. Brechet;J. Ansermet
在推广的不可逆热力学框架下，将变分原理应用于磁系统，我们发现铁磁体中温度梯度的存在导致了Landau-Lifshitz方程的推广，附加磁感场与温度梯度成正比。这个磁场调制了磁激励的衰减。它可以根据磁化波矢量相对于温度梯度的取向来增加或减小阻尼。这种变分方法证实了源于热力学的磁塞贝克效应的存在，并提供了对该效应强度的定量估计。
By applying a variational principle on a magnetic system within the framework of extended irreversible thermodynamics, we find that the presence of a temperature gradient in a ferromagnet leads to a generalisation of the Landau-Lifshitz equation with an additional magnetic induction field proportional to the temperature gradient. This field modulates the damping of the magnetic excitation. It can increase or decrease the damping, depending on the orientation of the magnetisation wave vector with respect to the temperature gradient. This variational approach confirms the existence of the magnetic Seebeck effect which was derived from thermodynamics and provides a quantitative estimate of the strength of this effect.