# Tunability of domain structure and magnonic spectra in antidot arrays of Heusler alloy

## TL;DR

This study demonstrates how the shape of antidots in Co-based Heusler alloy thin films can be used to tune magnonic spectra, revealing new control mechanisms for spin-wave modes in magnonic crystals.

## Contribution

It introduces shape-dependent tuning of magnonic spectra in antidot arrays of Heusler alloys, combining shape and magnetocrystalline anisotropy for enhanced control.

## Key findings

- Spin-wave spectra can be tuned by antidot shape.
- Shape and anisotropy influence internal field profiles.
- Antidot shape affects domain structure and switching behavior.

## Abstract

Materials suitable for magnonic crystals demand low magnetic damping and long spin wave (SW) propagation distance. In this context Co based Heusler compounds are ideal candidates for magnonic based applications. In this work, antidot arrays (with different shapes) of epitaxial $\mathrm{Co}_2\mathrm{Fe}_{0.4}\mathrm{Mn}_{0.6}\mathrm{Si}$ (CFMS) Heusler alloy thin films have been prepared using e-beam lithography and sputtering technique. Magneto-optic Kerr effect and ferromagnetic resonance analysis have confirmed the presence of dominant cubic and moderate uniaxial magnetic anisotropies in the thin films. Domain imaging via x-ray photoemission electron microscopy on the antidot arrays reveals chain like switching or correlated bigger domains for different shape of the antidots. Time-resolved MOKE microscopy has been performed to study the precessional dynamics and magnonic modes of the antidots with different shapes. We show that the optically induced spin-wave spectra in such antidot arrays can be tuned by changing the shape of the holes. The variation in internal field profiles, pinning energy barrier, and anisotropy modifies the spin-wave spectra dramatically within the antidot arrays with different shapes. We further show that by combining the magnetocrystalline anisotropy with the shape anisotropy, an extra degree of freedom can be achieved to control the magnonic modes in such antidot lattices.