# Current-driven nucleation and propagation of antiferromagnetic skyrmionium

## TL;DR

This paper theoretically investigates how antiferromagnetic skyrmioniums can be nucleated and propelled by spin currents, providing analytical and numerical insights into their creation and movement.

## Contribution

It introduces a new method for nucleating antiferromagnetic skyrmioniums using local spin current injection and derives an analytical expression for their velocity.

## Key findings

- Antiferromagnetic skyrmioniums can be generated via local spin current injection.
- Uniform spin currents can induce skyrmionium propagation.
- The derived velocity expression matches numerical simulations.

## Abstract

We present a theoretical study on nucleation and propagation of antiferromagnetic skyrmionium induced by spin current injection. A skyrmionium, also known as 2{\pi} skyrmion, is a vortex-like magnetic structure characterized by a topological charge, the so-called skyrmion number, being zero. We find that an antiferromagnetic skyrmionium can be generated via a local injection of spin current with toroidal distribution. A spatially uniform spin current is then demonstrated to induce a propagation of the skyrmionium. We derive an expression for the skyrmionium velocity based on a collective-coordinate model, which agrees well with our numerical results. Our findings suggest a novel way of nucleating an antiferromagnetic skyrmionium, as well as an analytical estimation of the current-driven skyrmionium velocity.