Micromagnetic methods for analyzing magnetization dynamics in ferromagnetic materials with the Landau-Lifshitz equation are described in detail. A method for including eddy currents in dynamic simulations is derived. The use of the fast Fourier transform for evaluating both the demagnetizing and eddy current fields is discussed.
Comparison of dynamic micromagnetic simulations to experimental data is utilized to measure the magnetic damping constant, and to test the domain of applicability of the Landau-Lifshitz equation. It is demonstrated that the Landau-Lifshitz equation only describes the dynamics of the local magnetization, not a macroscopic average.
Static micromagnetic models of the tips of write heads are utilized to study the effect of saturation on the write field. Transmission line and reluctance models of thin film write heads are presented. Finally, a dynamic model of a head, which combines a dynamic micromagnetic model of the yoke, including eddy current effects, with a saturating reluctance model of the neck and tip, is used to investigate the effects that various material and geometric parameters have on rise time.
My Research
