Influence of dipolar interactions on the superparamagnetic relaxation time of γ-Fe2O3

摘要: Influence of dipolar interactions on the Neel superparamagnetic relaxation time, τ , an assembly ultrafine ferromagnetic particles (γ-Fe2O3 ) with uniaxial anisotropy and different sizes has been widely studied using Mossbauer technique. These studies, based analytical approaches, have shown that decreases increasing between particles. To interpret these results, we propose a model where interaction effects are considered as being due to constant external randomly oriented magnetic field B(Ψ, ). The is resolution Fokker-Planck equation (FPE), generalizes previous calculations gives satisfactory interpretation phenomenon in such systems.