Carbon nanotube based magnetic tunnel junctions

Spin-coherent quantum transport in carbon nanotube magnetic tunnel junction s is investigated theoretically. A spin-valve effect is found for metallic, armchair tubes, with a magnetoconductance ratio ranging up to 20%. Because of the finite length of the nanotube junctions, transport is dominated by resonant transmission. The magnetic tunnel junctions are found to have dist inctly different transport behavior depending on whether or not the length of the tubes is commensurate with a 3N + 1 rule, with N the number of basic carbon repeat units along the nanotube length.