# Motion of skyrmions in nanowires driven by magnonic momentum-transfer forces

## TL;DR

This paper investigates how magnetic skyrmions move in nanowires under magnonic forces, revealing their trajectories depend on boundary interactions and current direction, with steady motion only for transverse magnon currents.

## Contribution

It combines micromagnetic simulations and Thiele equation analysis to elucidate skyrmion dynamics driven by magnon currents in nanowires, highlighting the effects of boundary forces and current orientation.

## Key findings

- Steady-state skyrmion motion occurs only with transverse magnon currents.
- Skyrmion velocity scales as J/α at low current densities.
- High current densities can destroy skyrmions by pushing them into the driving layer.

## Abstract

We study the motion of magnetic skyrmions in a nanowire induced by a spin-wave current $J$ flowing out of a driving layer close to the edge of the wire. By applying micromagnetic simulation and an analysis of the effective Thiele equation, we find that the skyrmion trajectory is governed by an interplay of both forces due to the magnon current and the wire boundary. The skyrmion is attracted to the driving layer and is accelerated by the repulsive force due to the wire boundary. We consider both cases of a driving longitudinal and transverse to the nanowire, but a steady-state motion of the skyrmion is only obtained for a transverse magnon current. For the latter case, we find in the limit of low current densities $J$ the velocity-current relation $v \sim J/\alpha$ where $v$ is the skyrmion velocity and $\alpha$ is the Gilbert damping. For large $J$ in case of strong driving, the skyrmion is pushed into the driving layer resulting in a drop of the skyrmion velocity and, eventually, the destruction of the skyrmion.