Influence of the system parameters on the non-Arrhenius magnetic relaxation of systems having distributed properties

Abstract

We have investigated, in the framework of the micromagnetic approximation, the relaxation behavior of both simple systems and systems having distributed properties. In the case of single-particle-type systems, our study focused on the exchange constant dependence of the so-called “waiting time” for the onset of the relaxation to conclude that this parameter linearly increased with the increase of the exchange constant. Our results for the relaxation of polycrystalline-type systems having distributed anisotropy easy axes showed the occurrence in limited time ranges of a magnetization decrease which was adequately fitted by the M(t)−M(0)∝ ln(t+t0) law. The exchange constant dependence of the additive fitting parameter in the logarithmic law qualitatively reproduced that of the waiting time indicating that both parameters were linked to the same underlying characteristic of the demagnetization process: the coupling of the magnetic moments forming the domain-wall-like structures through which the system reversed its magnetization.