Nonequilibrium Dynamics and Chaos of Domain-Wall Motion

The study of magnetic domain wall motion is important in both the field of power-magnetic microcores and in magnetic recording applications. The nonlinear differential equation for Bloch wall motion is obtained by modification of the Landau-Lifshitz-Gilbert equation. The terms of the nonlinear force of restitution and eddy current damping are added, and the equation is solved by using fourth order Runge-Kutta method. The tendency for the amplitude of magnetic domain wall motion to decrease with increasing layering frequency of the CoZrMo/SiO2 multilayered core is well reproduced by computer simulation. The irregular oscillation of the domain wall is found to be chaotic because a fractal structure is observed in the Poincare map. This result leads to a method for investigating energy loss and irregular phenomena (error or noise in magnetic recording systems) arising from magnetic domain wall oscillations.