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1.3 The Dynamic Equation

Up to now, we have presented a variational method based on the minimization of the free energy of a ferromagnetic body. This method allows one to find the equilibrium configurations for a magnetized body, regardless of describing how magnetization reaches the equilibrium during time. Recently, the challenging requirements of greater speed and areal density in magnetic storage elements, has considerably increased the effort of the researchers in the investigation of magnetization dynamics. Most of the analysis are based on the dynamic model proposed by Landau and Lifshitz [3] in 1935, and successively modified by Gilbert [18] in 1955. In this section we will present both Landau-Lifshitz and Gilbert equations as a model for magnetization `motion'. The differences between them are emphasized and the properties of magnetization dynamics are shown in view of the discussions and results presented in the following chapters.

Subsections

Massimiliano d'Aquino 2005-11-26