GMR in magnetic multilayers from a first principles band structure Kubo-Greenwood approach

We employ the Kubo-Greenwood formula to investigate from first-principles the giant magnetoresistance in Fe_mM_n (M=V, Cr, Mn and Cu) superlattices. The results indicate that MR can arise from band structure changes from ferromagnetic to anti-ferromagnetic alignments. Quantum confinement in the perpendicular direction is induced by the potential steps between the Fe and spacer layers and causes a much larger MR in the current-perpendicular-to-the-plane (CPP) geometry than in the current-in-plane (CIP) geometry. In the presence of the spin-orbit coupling interaction, MR is found to be reduced by spin-channel mixing