▎ 摘　　要

Based on a numerical study of a full-orbital tight-binding model, we show that magnetoresistance (MR) in ferromagnetic metal (FM)/graphene/FM lateral junctions originates from a spin-dependent shift of the Dirac points (DPs) caused by the presence of FM electrodes. Graphene with finite length L is in contact with FM at a zigzag edge and the spin-dependent conductance is calculated in the ballistic transport regime. We find that the tunneling conductance near DPs influences the features of the MR considerably. We further show that a slight change in the electronic structure near the DPs strongly affects the spin-dependent conductance resulting in a large MR ratio for an FM made of certain ferromagnetic transition metal alloys.