  We have demonstrated the deposition of EuO films on graphene by reactive
molecular beam epitaxy in a special adsorption-controlled and oxygen-limited
regime, which is a critical advance toward the realization of the exchange
proximity interaction (EPI). It has been predicted that when the ferromagnetic
insulator (FMI) EuO is brought into contact with graphene, an overlap of
electronic wavefunctions at the FMI/graphene interface can induce a large spin
splitting inside the graphene. Experimental realization of this effect could
lead to new routes for spin manipulation, which is a necessary requirement for
a functional spin transistor. Furthermore, EPI could lead to novel spintronic
behavior such as controllable magnetoresistance, gate tunable exchange bias,
and quantized anomalous Hall effect. However, experimentally, EuO has not yet
been integrated onto graphene. Here we report the successful growth of high
quality crystalline EuO on highly-oriented pyrolytic graphite (HOPG) and
single-layer graphene. The epitaxial EuO layers have (001) orientation and do
not induce an observable D peak (defect) in the Raman spectra. Magneto-optic
measurements indicate ferromagnetism with Curie temperature of 69 K, which is
the value for bulk EuO. Transport measurements on exfoliated graphene before
and after EuO deposition indicate only a slight decrease in mobility.
