MAGNETIZATION REVERSAL DYNAMICS IN ULTRATHIN MAGNETIC LAYERS

We propose an analytical expression of the magnetization reversal in u ltrathin magnetic layers, modeling the after effects, and taking into account both domain-wall motion and nucleation processes. We apply our modelization to quantify the dynamical properties of the magnetizatio n of MoS2/Au/Co/Au sandwiches: we define the Barkhausen volume, the wa ll velocity, and the nucleation rate depending an the applied magnetic field and the radius and the density of nuclei sites on the surface o f the sample. Finally, we investigate an original behavior of the swit ch of the magnetization in high dynamic regime. An attempt is mode to explain the divergence of the coercive field in large field variation rates (dH/dt), by introducing both the thermally activated and the vis cous processes driving the wall motion.