Magnetization switching in nanowires: Monte Carlo study with fast Fourier transformation for dipolar fields

Abstract

For the investigations of thermally activated magnetization reversal in systems of classical magnetic moments numerical methods are desirable. We present numerical studies which base on time quantified Monte Carlo methods where the long-range dipole-dipole interaction is calculated with the aid of fast Fourier transformation. As an example, we study models for ferromagnetic nanowires comparing our numerical results for the characteristic time of the reversal process also with numerical data from Langevin dynamics simulations where the fast Fourier transformation method is well established. Depending on the system geometry different reversal mechanism occur like coherent rotation, nucleation, and curling.

Magnetization reversal of ferromagnetic nanowires studied by magnetic force microscopy

“…The wires studied here have D p in the region where the transition between these two limiting situations takes place. 10 Hinzke and Nowak 26 have recently predicted that the reversal then resembles the nucleation of a domain at one of the ends of the wire in which the atomic spins in a plane perpendicular to the wire's long axis are not parallel, as for curling. We therefore expect that B c (Tϭ0) depends on D p , although not so strongly as for curling.…”

Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys

“…Note that the exchange interaction given by the matrices J ij is incorporated in our atomistic spin dynamics simulations via the fast Fourier transformation method (see Ref. [44] for more details). As a side effect, we are able to calculate the dipolar interaction without any additional computational effort so that we take them into account although they will not influence our results much.…”

Ferromagnetic Nanowires and Nanotubes

“…The rigorous micromagnetic simulations have been performed for single, isolated nanowires and elongated particles (Seberino & Bertram, 1999;Ferre et al, 1997;Hinzke & Nowak, 2000). In these cases, the magnetostatic interaction of neighbouring wires was generally omitted from the simulations.…”