Magnetic dielectric-graphene-ferroelectric system as a promising non-volatile device for modern spintronics

Abstract

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 nonvolatile spin filter. The practical application of the system under consideration would be restricted by a low Curie temperature of EuO. However, alternative magnetic insulators with high Curie temperature (e.g., Y3Fe5O12) can be used for a system operating under ambient conditions. Controlling the Fermi level (e.g., by temperature that changes ferroelectric polarization) can convert a spin filter to a spin valve.