Eur. Phys. J. B 73, 139-143 (2010)
https://doi.org/10.1140/epjb/e2009-00401-3

Spin filter effect and large magnetoresistance in the zigzag graphene nanoribbons

¹ College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.R. China
² National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P.R. China

Corresponding author: zpniu@nuaa.edu.cn

Received: 13 August 2009
Revised: 28 October 2009
Published online: 1 December 2009

Abstract

The spin filter effect and magnetoresistance (MR) in the graphene nanoribbons with zigzag edges have been investigated by the non-equilibrium Green's function method. Due to the spin-dependent current blocking effect, the ferromagnetic graphene/normal graphene junction can filter the spin in one direction, so a fully spin-polarized current is found. As the on-site energy μ_R in the right lead goes from negative to positive, the spin-down transmission would suddenly transforms from an 'ON' state to an 'OFF' state, however the spin-up transmission transforms from an 'OFF' state to an 'ON' state, so we can choose the current's spin polarized direction by tuning μ_R. For the ferromagnetic graphene/ferromagnetic graphene junction the current for the antiparallel magnetization configuration is blocked, a very large MR is obtained. It is expected that these features may serve as a type of useful spintronic devices in future.