  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.
