Multidimensional energy barrier distributions of interacting magnetic particles evaluated at different magnetization states

We evaluate the energy barrier distributions of coupled Co particles as a function of their concentration, which changes the strength of magnetostatic interactions, in a multidimensional space to take into account possible collective reversal. The distributions are evaluated at the remanence, demagnetized state and coercivity for Co particles with 2D random anisotropy easy axes orientations and with concentrations up to 56%. We show that the overall influence of interactions in this system is always to broad the energy barrier distribution. Consequently, in all the cases the magnetization decay would start earlier when the strength of interactions increases. At the remanence, strong interactions displace the average energy barrier to larger values. However, at the coercive force it is displaced to smaller values. At the same time, at the demagnetized state, the peak of the distribution practically remains at the same position. © 2005 American Institute of Physics. fDOI: 10.1063/1.1853834g