Robust formation of skyrmions and topological Hall effect in epitaxial thin films of MnSi

TL;DR

This study demonstrates the stable formation of skyrmions and a topological Hall effect in epitaxial MnSi thin films, revealing unique features like a shorter spin helix period and opposite THE sign, expanding understanding of skyrmion physics.

Contribution

It reports the first observation of robust skyrmions and topological Hall effect in epitaxial MnSi films with novel features not seen in bulk material.

Findings

Skyrmions are stable over a wide temperature-magnetic field range.

Epitaxial MnSi films exhibit a shorter spin helix period.

The sign of the topological Hall effect is opposite to that in bulk MnSi.

Abstract

Magneto-transport properties have been investigated for epitaxial thin films of B20-type MnSi grown on Si(111) substrates. Both Lorentz transmission electron microscopy (TEM) images and topological Hall effect (THE) clearly point to the robust formation of skyrmions over a wide temperature-magnetic field region. New features distinct from those of bulk MnSi are observed for epitaxial MnSi films: a shorter (nearly half) period of the spin helix and skyrmions, and an opposite sign of THE. These observations suggest versatile features of skyrmion-induced THE beyond the current understanding.