Dipolar ordering in assemblies of nanomagnets

Abstract

In this work, we have set up a computer code to simulate the magnetic equilibrium state of magnetic nanostrutures with different shapes. Dipolar interactions among the magnetic moments have been taken into account and an efficient algorithm to compute the fields during the Monte Carlo simulation has been devised. We have used the code to check the limits of validity of the macrospin approximation for the dipolar fields and we have applied it to study the ground states of assemblies of nanostructures. Finally, we show that simulations with atomistic detail are able to reproduce the known magnetic states in disc-shaped elements and find that the magnetic states of cubic nanoparticles can be tuned by their size in good agreement with experimental observations