Effect of the attachment of ferromagnetic contacts on the conductivity and giant magnetoresistance of graphene nanoribbons

Abstract

Carbon-based nanostructures and graphene, in particular, evoke a lot of interest as new promising materials for nanoelectronics and spintronics. One of the most important issues in this context is the impact of external electrodes on the electronic properties of graphene nanoribbons (GNRs). The present theoretical method is based on the tight-binding model and a modified recursive procedure for Green’s functions. The results show that within the ballistic transport regime, the so-called end-contacted geometry (of minimal GNR/electrode interface area), is usually more advantageous for practical applications than its side-contacted counterpart (with a larger coverage area), as far as the electrical conductivity is concerned. As regards the giant magnetoresistance coefficient, however, the situation is exactly the opposite, since spin-splitting effects are more pronounced in the lower conductive side-contacted setups.