  Scalable fabrication of magnetic 2D materials and heterostructures
constitutes a crucial step for scaling down current spintronic devices and the
development of novel spintronic applications. Here, we report on van der Waals
(vdW) epitaxy of the layered magnetic metal Fe$_3$GeTe$_2$ - a 2D crystal with
highly tunable properties and a high prospect for room temperature
ferromagnetism - directly on graphene by employing molecular beam epitaxy.
Morphological and structural characterization confirmed the realization of
large-area, continuous Fe$_3$GeTe$_2$/graphene heterostructure films with
stable interfaces and good crystalline quality. Furthermore, magneto-transport
and X-ray magnetic circular dichroism investigations confirmed a robust
out-of-plane ferromagnetism in the layers, comparable to state-of-the-art
exfoliated flakes from bulk crystals. These results are highly relevant for
further research on wafer-scale growth of vdW heterostructures combining
Fe$_3$GeTe$_2$ with other layered crystals such as transition metal
dichalcogenides for the realization of multifunctional, atomically thin
devices.
