A model for thermal spin relaxation in rotating ferromagnetic clusters

A model for thermal spin relaxation in isolated ferromagnetic clusters is proposed and investigated theoretically by means of nonequilibrium thermodynamics. It is shown that thermal agitation mediates relaxation of the spin towards the total angular momentum vector of the cluster so that the clusters are magnetically polarized in the direction of their rotational axis. A relaxation mechanism via thermal moment of inertia fluctuations is proposed. The results are discussed for a Fe₁₂₅-cluster.