Spin-polarized transport in graphene nanoribbons with one paramagnetic lead and one ferromagnetic lead

This paper is devoted to theoretical studies on spin-sensitive transport in graphene nanoribbons sandwiched between two metallic contacts out of which one is paramagnetic and the other ferromagnetic. The attention is directed to the spin polarization of the current (conductance) and atom projected densities of states in the vicinity of the ferromagnetic drain electrode. It turns out that the spin polarization of the conductance depends strongly on the current direction (zigzag versus armchair transport direction), as well as on the aspect ratio of the ribbon. The effect is typically of a few tens percent, and can be effectively controlled electrically (by gating). It is suggested that quasi-ballistic spin transport through graphene may be experimentally realized with Pd (paramagnetic) and Ni-Pd (ferromagnetic) electrodes.