Ferromagnetic resonance study of thin film antidot arrays: Experiment and micromagnetic simulations

Abstract

The dynamic magnetic properties of two-dimensional periodic Co antidot arrays were studied by X-band ferromagnetic resonance. The experimental results on geometrically scaled antidot arrays reveal a strong attenuation of the uniform ferromagnetic resonance mode in comparison to a continuous film, but an excitation of nonuniform in-plane spin-wave modes. Micromagnetic finite-element simulations show that the static magnetic structure in an antidot array depends on the direction of the external field with respect to the symmetry axes of the antidot lattice, even if the external field is strong enough to enforce a technically saturated magnetization state. The analysis gives evidence that characteristic inhomogeneities in the magnetization distribution around the antidots give rise to the changes of the resonance modes with the in-plane direction of the magnetization.

Generation of propagating spin waves from regions of increased dynamic demagnetising field near magnetic antidots

“…Expectedly, this leads to a local reduction of the internal field. 29 In contrast, the total internal field at the left and right sides of the antidot is actually increased, due to the demagnetizing field aligning with the bias field. This behavior of the demagnetizing field resembles the field of an isolated dipole and is therefore also anticipated.…”

“…The results presented here are applicable to the interpretation of the magnetization dynamics in magnonic antidot arrays (which have been extensively studied, e.g., in Refs. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46], while also elaborating the interpretation of the spin-wave scattering that was experimentally and theoretically studied in Ref. 25.…”

A micromagnetic study of the reversal mechanism in permalloy antidot arrays

“…[30][31][32] Other important efforts have been made to investigate dynamic properties, focusing on ferromagnetic resonance phenomena and spin-wave propagation for possible application in magnetic logic devices. [33][34][35][36][37][38][39][40][41] A fundamental support to understand the complex magnetic behavior of antidot arrays has been found in micromagnetic simulations based on the solution of the LandauLifshitz equation. 42,43 To limit the computational time and the memory requirements, the micromagnetic simulations have often been performed by introducing periodic boundary conditions on the edges of the unit cell that defines the spatial period.…”

Generation of Propagating Spin Waves From Edges of Magnetic Nanostructures Pumped by Uniform Microwave Magnetic Field

“…This mechanism is capable of exciting both magneto-dipole and dipole-exchange spin waves, depending on the frequency of excitation and / or the film thickness. Furthermore, the uniformity of the exciting magnetic field implies that the excitation could also accompany such common measurement techniques of magnonics as cavity and waveguide based ferromagnetic resonance spectroscopy [28], time-resolved scanning Kerr microscopy [1] and microwave assisted Brillouin Light Scattering imaging [14], [20].…”