  We previously show [JETP Letters, {\bf 114}, 763 (2021)] that a graphene
sample placed on a ferromagnetic substrate demonstrates a cooperative
magnetoelectronic instability. The instability induces a gap in the electronic
spectrum and a canting deformation of the magnetization near the
graphene-substrate interface. In this paper we prove that the interaction
between the electrons in graphene strongly enhances the instability. Our
estimates suggest that in the presence of even a moderate interaction the
instability can be sufficiently pronounced to be detected experimentally in a
realistic setting.
