  A spin field effect transistor (FET) is proposed by utilizing a graphene
nanoribbon as the channel. Similar to the conventional spin FETs, the device
involves ferromagnetic metals as a source and drain; they, in turn, are
connected to the graphene channel. Due to the negligible spin-orbital coupling
in the carbon based materials, the bias can accomplishes spin manipulation by
means of electrical control of electron exchange interaction with a
ferromagnetic dielectric attached to the nanoribbon between source and drain.
The numerical estimations show the feasibility of graphene-based spin FET if a
bias varies exchange interaction on the amount around 5 meV. It was shown that
the device stability to the thermal dispersion can provide the armchair
nanoribbons of specific width that keeps the Dirac point in electron dispersion
law.
