Particle-like topological magnetic defects that can propagate in all spatial directions open a new dimension for design of magnetic memory and data processing devices. We show that three-dimensional magnetic skyrmions can be stabilized in non-collinear antiferromagnets, such as the Fe-langasite, Ba3TaFe3Si2O14. Spins in the crystallographic unit cell of this material form a 120-degree ordering transformed by competing exchange interactions into a short-period spiral, which in turn forms a basis for complex large-scale magnetic superstructures stabilized by Dzyaloshinskii-Moriya interactions and applied magnetic fields. We derive an effective continuum model describing modulated states of Fe-langasite at the 100 nm scale and explore its magnetic phases and topological defects. The order parameter space of this model is similar to that of superfluid 3He-A and the three-dimensional topological defect is closely related to the Shankar monopole and hedgehog soliton in the Skyrme model of baryons.
@article{arxiv.2106.11910,
title = {Magnetic particles and strings in iron langasite},
author = {Evgenii Barts and Maxim V. Mostovoy},
journal= {arXiv preprint arXiv:2106.11910},
year = {2022}
}