M. Mruczkiewicz, P. Gruszecki, M. Zelent, and M. Krawczyk

Phys. Rev. B 93, 174429 (2016)

We investigate theoretically themagnetization dynamics in a skyrmionmagnonic crystal. Collective excitations are studied in a chain of touching ferromagnetic nanodots in a skyrmion magnetic configuration. The determined dispersion relation of coupled skyrmions shows a periodic dependence on the wave vector, a characteristic feature of the band structure in magnonic crystals. By spatial analysis of the magnetization amplitude in the magnonic bands we identify the excited modes as breathing and clockwise gyrotropic dynamic skyrmions. Propagating with a negative and positive group velocity, respectively, these high- and low-frequency excitations can be further explored theoretically and experimentally for fundamental properties and technological applications in spintronics and magnonics.

Fig.1. Structures considered in this study, with an out-of-plane bias magnetic field Bz directed along the z axis.