Magnetic configurations and switching processes in cobalt ferromagnetic hollow nanospheres

We present a study about the magnetization reversal of cobalt hollow-spheres by micromagnetic simulation using Nmag. The magnetization reversal and switching processes as a function of the geometric parameter were analyzed. In this way, we can verify exactly in which condition each mode arises during the inversion of the external field for a single cobalt hollow-sphere. All the predicted modes can occur in the hysteresis curve, for an external radius of 30 nm. For 20 nm spheres, only the coherent reversal appears throughout the hysteresis curve, as predicted in analytical calculations. (paper)