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.
@article{arxiv.1904.06870,
title = {Current-driven nucleation and propagation of antiferromagnetic skyrmionium},
author = {S. A. Obadero and Y. Yamane and C. A. Akosa and G. Tatara},
journal= {arXiv preprint arXiv:1904.06870},
year = {2020}
}