▎ 摘　　要

In this paper the parallel and antiparallel graphene based Ferromagnet-Normal-Ferromagnet (FNF) structures are investigated theoretically. Effect of parallel and antiparallel alignments strength of ferromagnets and thickness of normal region and temperature on the charge, spin and thermal conductances are studied. A survey on Giant magnetoresistance (GMR) has been done and we have shown that, conductances of parallel and antiparallel structures are different. In this paper, we study and calculate all kinds of the GMR including the charge-GMR, thermal-GMR and also spin-GMR for a FNF systems. Although the charge-GMR is important and useful in fabrication magnetic information storage has been investigated in many works but few papers exist about thermal-GMR and spin-GMR. Also with consideration spin current we observed that, in definite strength of ferromagnetic film and in the presence of charge current, spin current is zero. This latter case can be used as a spin-valve. (C) 2011 Elsevier B.V. All rights reserved.