Micromagnetic calculation of the high frequency dynamics of nano-size rectangular ferromagnetic stripes

Abstract

Nano-size ferromagnetic dots, wires, and stripes are of great interest for future high speed magnetic sensors and ultrahigh density magnetic storage. High frequency dynamic excitation is one way to investigate the time scale of the magnetization reversal in submicron particles with lateral nanometer dimension. Macroscopic models like the Landau–Lifshitz (LL) model are often used to describe the switching process. However, these models do not take into account the nonuniformity of the magnetization structure. In this article dynamic micromagnetic calculations are used in determining the high frequency susceptibility of a 1 μm×50 nm×5 nm Permalloy stripe. The studied structure exhibits two resonance modes. The higher, primary peak is around 10 GHz and can be identified with the uniform resonance mode predicted by the macroscopic LL model. The low frequency peak is attributed to the splay of the magnetization distribution near the end of the stripe.

Micromagnetic Simulations of Vortex Resonances in Coupled Nanodisks

“…Then, different strategies developed in the last decade can be used to compute the dynamic response. The most popular approach is the time domain method which is based on the direct integration of the equation of motion for magnetization and the use of a time-frequency transform to get the susceptibility spectra [18]- [20]. The second one is the frequency domain method we developed ten years ago [21], [22].…”

Edge saturation fields and dynamic edge modes in ideal and nonideal magnetic film edges

“…[31][32][33] First, we used an energy minimization scheme to allow the magnetization to come to equilibrium in the applied field. The magnetization dynamics were then excited by a short, spatially uniform field pulse.…”

High-frequency response of nanostructured magnetic materials

“…A tricky point is the choice of the temporal shape of the exciting field in order to ensure that the magnetization dynamics stays in the linear regime and to probe the frequency range of interest. This approach was first applied to the highfrequency response of nano-sized rectangular ferromagnetic stripes [7] and to the computation of ferromagnetic resonance (FMR) spectra of submicrometer-sized circular elements [8,9]. The latter method consists in linearizing the equation for magnetization motion around the equilibrium magnetization configuration M eq (r) in order to compute the linear magnetic response dm to a weak uniform exciting field dh.…”