Effect of the dipolar coupling on the precessional magnetization switching in two-dimensional arrays of single-domain nano-ellipses

Abstract

Various spintronic devices use single-domain magnetic nanoparticles as unit cells. Herein, we investigated interparticle dipole-dipole interactions in arrays of Permalloy single-domain nano-ellipses through micromagnetic simulations. In this study, the variation is introduced not only to the aspect ratio and the spacing between ellipses but to the magnetization distribution and the 2D lattice type as well. When integrating the Landau-Lifshitz-Gilbert equation with zero external magnetic field, equilibrium magnetic configurations were obtained for each array. For small values of the spacing between ellipses, they interact strongly, such that the shape anisotropy is locally modified by the distribution of the magnetization. Moreover, the effect of the dipolar coupling on the precessional magnetization reversal is also studied. The minimum field strength required to switch the magnetization depends on the magnetization distribution in a strongly interacting magnetic system. Consequently, we have assessed the minimum spacing between particles in which single-domain nano-ellipses becomes a non-interacting magnetic system.