# Current-Driven Dynamics of Magnetic Hopfions

## TL;DR

This paper explores the excitation and current-driven manipulation of three-dimensional magnetic hopfions, revealing their potential as stable information carriers due to their unique topological properties and absence of Hall effects.

## Contribution

It demonstrates the existence of metastable Bloch- and Ne9el-type hopfions in ferromagnets and analyzes their dynamics under spin-transfer and spin-Hall torques.

## Key findings

- Ne9el-type hopfions can be driven along the current direction by STT and SHT.
- Bloch-type hopfions can be moved transverse or parallel to current depending on the torque.
- Hopfions lack a gyrovector, eliminating Hall effects in their motion.

## Abstract

Topological magnetic textures have attracted considerable interest since they exhibit new properties and might be useful in information technology. Magnetic hopfions are three-dimensional (3D) spatial variations in the magnetization with a non-trivial Hopf index. We find that in ferromagnetic materials, two types of hopfions, Bloch-type and N\'{e}el-type hopfions, can be excited as metastable states in the presence of bulk and interfacial Dzyaloshinskii-Moriya interactions, respectively. We further investigate how hopfions can be driven by currents via spin-transfer torques (STTs) and spin-Hall torques (SHTs). Distinct from 2D ferromagnetic skyrmions, hopfions have a vanishing gyrovector. Consequently, there are no undesirable Hall effects. N\'{e}el-type hopfions move along the current direction via both STT and SHT, while Bloch-type hopfions can be moved either transverse to the current direction by SHT or parallel to the current direction by STT. Our findings open the door to utilizing hopfions as information carriers.