Edge localization of spin waves in antidot multilayers with perpendicular magnetic anisotropy

TL;DR

This study investigates how antidot shape variations in Co/Pd multilayers with perpendicular magnetic anisotropy affect spin-wave spectra, revealing localized modes around antidots that could enhance magnonic device design.

Contribution

It demonstrates the influence of antidot shape on spin-wave spectra and identifies localized modes related to reduced anisotropy regions, advancing magnonics research.

Findings

Antidot shape significantly alters spin-wave spectra.

Localized spin-wave modes are associated with shell regions around antidots.

Reduced anisotropy in shell regions enables tunable magnonic properties.

Abstract

We study the spin-wave dynamics in nanoscale antidot lattices based on Co/Pd multilayers with perpendicular magnetic anisotropy. Using time-resolved magneto-optical Kerr effect measurements we demonstrate that the variation of the antidot shape introduces significant change in the spin-wave spectra, especially in the lower frequency range. By employing micromagnetic simulations we show that additional peaks observed in the measured spectra are related to narrow shell regions around the antidots, where the magnetic anisotropy is reduced due to the Ga+ ion irradiation during the focused ion beam milling process of the antidot fabrication. The results point at new possibilities for exploitation of localized spin waves in out-of-plane magnetized thin films, which are easily tunable and suitable for magnonics applications.