▎ 摘　　要

Spin-polarized transports of relativistic electrons through graphene-based ferromagnet/insulator/ferromagnet (FG/IG/FG) single junctions have been investigated theoretically. Large oscillating tunnel magnetoresistance (TMR) has been found in monolayer and bilayer FG/IG/FG junctions. The oscillating amplitudes of TMR do not decrease with the increase of the thickness and the height of barrier, in contrast to the exponential decay in conventional ferromagnet/insulator/ferromagnet single junction. The physical origin for such a phenomenon has also been analyzed. It is anticipated to apply such a phenomenon to design the spin-polarized electron device based on the graphene materials. (c) 2007 Elsevier B.V. All rights reserved.