# Dynamics of a magnetic skyrmionium in an anisotropy gradient

## TL;DR

This paper investigates the movement of magnetic skyrmionium under an anisotropy gradient, revealing efficient straight-line motion with minimal Hall angle and potential for racetrack memory applications.

## Contribution

It demonstrates a new method to drive skyrmionium efficiently using anisotropy gradients and explores how damping and nanowire width affect its stability and motion.

## Key findings

- Skyrmionium moves straight along the gradient with near-zero Hall angle.
- Speed of skyrmionium is significantly higher than skyrmion.
- Motion depends on damping coefficient and nanowire width.

## Abstract

Magnetic skyrmionium is a novel magnetization configuration with zero skyrmion number, which is composed by two skyrmions with opposite skyrmion number. Here, we study the dynamics of skyrmionium under an anisotropy gradient. We find that the skyrmionium can be efficiently driven by an anisotropy gradient with moving straightly along the direction of gradient. The skyrmion Hall angle for skyrmionium is close to zero which is much smaller than that of skyrmion. while the speed is much larger. We also demonstrate that the skyrmionium motion depends on the damping cofficient, and the skyrmionium stabilization in the motion can be modulated by narrowing the width of the nanowire. Our work shows a efficient driven method for skyrmionium, which may be promising in the application of skyrmionium based racetrack memory.