Berlin 2024 – scientific programme

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MA: Fachverband Magnetismus

MA 20: Poster I

MA 20.15: Poster

Tuesday, March 19, 2024, 16:30–19:00, Poster A

Micromagnetic simulations of spin wave propagation in corrugated waveguides — •Ashfaque Thonikkadavan and Riccardo Hertel — Université de Strasbourg and CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, F-67000 Strasbourg, France

The spin-wave dynamics in ferromagnets with periodic patterning can display properties of magnonic crystals, like the appearance of magnon band structures with forbidden frequency gaps. A wide variety of magnonic crystals have been investigated over the past years, including arrays of spatially separated nanomagnets and magnetic thin films with periodically modulated material parameters. Progress in three-dimensional magnetic nanofabrication has made it possible to study systems with geometric, rather than structural, modulations. Here, we investigate the magnonic properties of a micron-sized Permalloy thin-film element with a sinusoidally undulated surface using finite-element micromagnetic simulations. In this case, the surface curvature varies periodically, with sub-micron periodicity, while the magnetic material properties and the film thickness (10 nm) are constant throughout the sample. The curvature induces a local shape anisotropy sufficiently strong to align the magnetization perpendicular to the corrugation direction at zero field. We study the spin-wave propagation in Damon-Eshbach geometry and its dependence on the periodicity and amplitude of the modulation. We find that the system shows features of a gapless one-dimensional magnonic crystal. In contrast, a band gap develops when an external field is applied along the corrugation direction, i.e., in the case of backward-volume spin waves.

Keywords: Magnonic crystals; Micromagnetic Simulation; Three-dimensional Nanomagnetism