Collective dynamical skyrmions excitations in magnonic crystal

TL;DR

This paper theoretically explores the collective excitations of skyrmion magnetization in a chain of ferromagnetic nanodots, revealing band structures and mode types relevant for spintronics and magnonics.

Contribution

It introduces the concept of collective skyrmion excitations in a magnonic crystal and analyzes their dispersion relations and mode characteristics.

Findings

Presence of periodic band structure in skyrmion excitations

Identification of breathing and gyrotropic modes

Propagation of excitations with positive and negative group velocities

Abstract

We investigate theoretically skyrmion magnonic crystal, i.e., the dynamics of the magnetization in a chain of the ferromagnetic nanodots being in skyrmion magnetic configuration. We show that collective excitations are possible to be observed in the structure. We present the dispersion relation of the coupled skyrmions. It exhibit a periodical property in dependence on wave vector, characteristic feature of the band structure in magnonic crystals. Spatial analysis of the magnetization amplitude associated with the magnonic bands confirms type of the excited modes, as breathing and clockwise gyrotropic dynamical skyrmions. These high and low frequency excitations, propagate with negative and positive group velocity, respectively, and can be explored for study fundamental properties and technological applications in spintronics and magnonics.