Coexistence of large anomalous Hall effect and topological magnetic skyrmions in a Weyl nodal ring ferromagnet Mn5Ge3

TL;DR

This study demonstrates the coexistence of a large anomalous Hall effect and magnetic skyrmions in Mn5Ge3, a Weyl nodal ring ferromagnet, revealing its potential for spintronics applications through combined experimental and theoretical analysis.

Contribution

It uncovers the simultaneous presence of topological Hall effects and skyrmions in Mn5Ge3, a magnetic topological nodal-line semimetal, with detailed transport, TEM, and theoretical insights.

Findings

Intrinsic anomalous Hall conductivity up to 979.7 S/cm.

Presence of magnetic skyrmions over wide temperature-magnetic field ranges.

Large topological Hall effect linked to Weyl nodal rings.

Abstract

Topological magnetic materials are expected to show multiple transport responses because of their unusual bulk electronic topology in momentum space and topological spin texture in real space. However, such multiple topological properties-hosting materials are rare in nature. In this work, we reveal the coexistence of a large tunable anomalous Hall effect and topological magnetic skyrmions in a Weyl nodal ring ferromagnet Mn5Ge3, by using electrical transport and Lorentz transmission electronic microscope (TEM) measurements. It was found that the intrinsic anomalous Hall conductivity (AHC) can reach up to 979.7 S/cm with current along [120] and magnetic field along [001] of the Mn5Ge3 single crystals. Our theoretical calculations reveal that the large AHC is closely related with two Weyl nodal rings in band structure near the Fermi level and is strongly modified by the content of Ge. Moreover, our Lorentz-TEM images and micromagnetic simulation results, together with the sizable topological Hall effect clearly point to the robust formation of magnetic skyrmions over a wide temperature-magnetic field region. These results prove Mn5Ge3 as a rare magnetic topological nodal-line semimetal with great significance to explore novel multiple topological phenomena, which facilitates the development of spintronics.