The effect of dry friction on Domain Wall dynamics: a micromagnetic study

In this paper a numerical investigation of the effects of disorder on the domain wall propagation along magnetic nanostrips induced by fields or currents is carried out. Such effects are included in the extended Landau-Lifshitz-Gilbert equation of motion by generalizing the classical viscous-type dissipation function through the addition of a nonlinear dry friction contribution. The key dynamical features observed by using this approach are: (i) the existence of a propagation threshold for both fields and currents; (ii) the reduction (increase) of the domain wall velocity in the steady-state (precessional) regime; (iii) the independence (dependence) of the velocity achieved at the Walker-type breakdown of (on) the dry-friction coefficient in the case of a field- (current-) driven motion. Our results qualitatively agree with previous numerical models of disorder which make use of different assumptions, mainly based on the spatial fluctuation of the material properties.