Optimal conditions for magnetization reversal of nanocluster assemblies with random properties

Abstract

Magnetization dynamics in the system of magnetic nanoclusters with randomly distributed properties are studied by means of computer simulations. The main attention is paid to the possibility of coherent magnetization reversal from a strongly nonequilibrium state with a mean cluster magnetization directed opposite to an external magnetic field. Magnetic nanoclusters are known to be characterized by large magnetic anisotropy and strong dipole interactions. It is also impossible to produce a number of nanoclusters with identical properties. As a result, any realistic system of nanoclusters is composed of the clusters with randomly varying anisotropies, effective spins, and dipole interactions. Despite this randomness, it is possible to find conditions when the cluster spins move coherently and display fast magnetization reversal due to the feedback action of resonator. By analyzing the influence of different cluster parameters, we find their optimal values providing fast magnetization reversal.