Magnetoresistance in Bilayer Graphene Hybrid Structures for Spintronic Applications

A drastic modification of electronic band structure leading to potential spin device applications is predicted in bilayer graphene (BLG) when it is placed between two ferromagnetic insulators. The composite resembles a ferromagnet-metal hybrid structure that has a giant magneto-resistance owing to the spin-dependent conductivity. The bottom ferromagnetic dielectric layer (FDL) possesses the magnetization M₁ that can be pinned along the direction of the x-axis by an anti-ferromagnetic substrate. The top FDL may be constructed from the same material but its magnetization vector M₂ can be rotated on the x-y plane (by an external magnetic field) forming an angle with M₁. The influence of FDL magnetization on BLG electronic structure can be realized through either the direct exchange interaction with magnetic ions (assuming an overlap between the carbon pi-orbitals and unfilled shells of the magnetic ions in FDLs) or an indirect interaction via the ligands of FDLs. The structure is modeled.