Magnetic Microscopy of Skyrmions in Magnetic Thin Films with Chiral Overlayers

TL;DR

This study uses NV magnetometry to image and analyze how chiral overlayers influence skyrmion properties in magnetic thin films, revealing potential for molecular control of topological spin textures.

Contribution

It demonstrates direct imaging and quantitative analysis of skyrmions in chiral-molecule-functionalized films, uncovering enantioselective and magnetic-field-dependent effects.

Findings

Skyrmion diameter, spacing, and shape are affected by chiral overlayers.

Reproducible nucleation and probing of skyrmions in CoFeB films.

Evidence of magneto-chiral coupling enabling molecular control of skyrmions.

Abstract

Topologically nontrivial magnetic textures such as skyrmions offer promising opportunities for spintronic applications. In recent years, it has been shown that the magnetic properties of layered materials can be affected by depositing chiral molecules on the surface, while the influence of chiral overlayers on skyrmion properties such as their stability and interactions remains largely unexplored. To address this challenge, we employ wide-field nitrogen-vacancy (NV) magnetometry to directly image skyrmions in chiral-molecule-functionalized magnetic thin films, enabling quantitative mapping of magnetic stray fields over extended areas under ambient conditions. Using pixel-resolved optically detected magnetic resonance (ODMR) combined with controlled magnetic fields, we reproducibly nucleate and probe skyrmion states in CoFeB ferromagnetic samples, enabling quantitative investigation of their properties. We find evidence for enantioselective and magnetic-field-polarity-dependent modifications of skyrmion diameter, spacing, and shape, pointing to a possibility of molecular control of topological spin textures via magneto-chiral coupling.