Fractional Skyrmion Tubes in Chiral-Interfaced Three-Dimensional Magnetic Nanowires

TL;DR

This paper reports the creation of fractional Bloch skyrmion tubes in 3D-printed ferromagnetic nanowires with opposite chirality regions, revealing new topological spin textures at room temperature for potential spintronics applications.

Contribution

It introduces a novel method to generate and control fractional skyrmion tubes in 3D nanowires with chiral interfaces, expanding the understanding of topological spin textures.

Findings

Fractional skyrmion tubes form at zero magnetic field.

Control over vortex and skyrmion-vortex states demonstrated.

Room temperature stability of these topological textures confirmed.

Abstract

Magnetic skyrmions are chiral spin textures with rich physics and great potential for unconventional computing. Typically, skyrmions form in bulk crystals with reduced symmetry or ultrathin film multilayers involving heavy metals. Here, we demonstrate the formation of fractional Bloch skyrmion tubes at room temperature by 3D printing ferromagnetic double-helix nanowires with two regions of opposite chirality. Using X-ray microscopy and micromagnetic simulations, we show that the coexistence of vortex and anti-parallel spin states induces the formation of fractional skyrmion tubes at zero magnetic fields, minimising the energy cost of breaking the coupling between geometric and magnetic chirality. We also demonstrate control over zero-field states, including pure vortex, or mixed skyrmion-vortex states, highlighting the magnetic reconfigurability of these 3D nanowires. This work shows how interfacing chiral geometries at the nanoscale can enable advanced forms of topological spintronics.