  The conductivity of the system magnetic dielectric (EuO) - graphene channel -
ferroelectric substrate was considered. The magnetic dielectric locally
transforms the band spectrum of graphene by inducing an energy gap in it and
making it spin-asymmetric with respect to the free electrons. The range of
spontaneous polarization (2- 5)mC/m2 that can be easily realized in thin films
of proper and incipient ferroelectrics, was under examination. It was
demonstrated, that if the Fermi level in the graphene channel belongs to energy
intervals where the graphene band spectrum, modified by EuO, becomes sharply
spin-asymmetric, such a device can be an ideal non-volatile spin filter.
Controlling of the Fermi level (e.g. by temperature that changes ferroelectric
polarization) can convert a spin filter to a spin valve.
