Dimensionality effects on the magnetisation processes in arrays of superparamagnetic nanoparticles

Abstract

We analyse the effect of inter-particle coupling and clustering on the zero-field cooled (ZFC) magnetisation processes of superparamagnetic nanoparticles. The static interaction field in dense assemblies of nanoparticles of different dimensionalities (1D, 2D and 3D) is investigated by numerical micromagnetic simulations. An analytical model is then used in order to evaluate the influence of the dimensionality of these systems on the topology of zero-field cooled magnetisation processes. Mutual static magnetic interactions are almost negligible in 3D arrays but become very important in systems of reduced dimensionality such as chains or layers of nanoparticles and they can account for up to 20% shift in the peak temperature of ZFC curves. The present results can be useful in evaluate the influence of interactions on the topology of ZFC magnetisation curves.