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
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 μR 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 μR. 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.
PACS: 72.25.-b – Spin polarized transport / 73.40.Gk – Tunneling / 85.75.-d – Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009