  The exchange splitting and resulting electromagnetic response of graphene in
a monolayer chromium triiodide(CrI3) graphene van der Waals(vdW)
heterostructure are considered using a combination of density functional theory
and electromagnetic calculations. Although the effective exchange fields are in
the hundreds of Tesla, for the equilibrium separation non reciprocal effects
are found to be weak compared to those for a comparable external magnetic bias.
For non equilibrium separations, nonreciprocal effects can be substantial.
