A voltage switchable non-local spin-FET is disclosed which provides a layer of chromia over a ferromagnetic substrate, such as cobalt. A film of graphene overlays the chromia, with a protective layer of metal oxide like cobalt oxide or iron oxide there between to prevent catalytic degradation of the graphene, which may occur. The graphene is provided with a contact, or source and drain, depending on the application. The spin-FET, which exhibits magnetic remanence, may be provided with a top gate of, e.g., cobalt or other ferromagnet such as iron. As an alternative to the ferromagnetic substrate, the device may be formed on a silicon or gallium arsenide base, or directly on a metal interconnect of an integrated circuit.