In physics, the Landau–Lifshitz–Gilbert equation, named for Lev Landau, Evgeny Lifshitz, and T. L. Gilbert, is a name used for a differential equation describing the precessional motion of magnetization M in a solid. It is a modification by Gilbert of the original equation of Landau and Lifshitz.
The various forms of the equation are commonly used in micromagnetics to model the effects of a magnetic field on ferromagnetic materials. In particular it can be used to model the time domain behavior of magnetic elements due to a magnetic field. An additional term was added to the equation to describe the effect of spin polarized current on magnets.
参考资料：
https://en.wikipedia.org/wiki/Landau–Lifshitz–Gilbert_equation
https://zh.wikipedia.org/wiki/朗道-利夫希兹方程
https://baike.baidu.com/item/朗道-利夫希兹方程/22761190