| AVS 56th International Symposium & Exhibition | |
| Graphene Topical Conference | Wednesday Sessions |
| Session GR+MI-WeM |
| Session: | Spins in Graphene: Injection and Manipulation |
| Presenter: | W. Han, University of California, Riverside |
| Authors: | W. Han, University of California, Riverside K. Pi, University of California, Riverside K. McCreary, University of California, Riverside W. Bao, University of California, Riverside C.N. Lau, University of California, Riverside R. Kawakami, University of California, Riverside |
| Correspondent: | Click to Email |
Single-layer graphene (SLG) is an attractive material for spintronics due to its tunable carrier concentration and polarity, weak spin-orbit coupling, its quasi-relativistic band structure with symmetric electron and hole bands. We fabricated the SLG spin valves using transparent Co/SLG contacts and studied the spin dependent properties by non-local magnetoresistance (MR) measurements at room temperature. Hanle effect confirms that the non-local signal originates from spin injection and transport and gives a spin relaxation time of ~84 ps and a spin diffusion length of ~1.5 μm. Spacing dependence of the non-local MR indicates a spin diffusion length of ~1.6 μm and a spin injection/detection efficiency of 0.43. Gate voltage dependence shows that the non-local MR is proportional to the conductivity of the SLG, which is the predicted behavior for transparent ferromagnetic/nonmagnetic contacts. Bias dependence of the non-local MR reveal an electron-hole asymmetry in which the non-local MR is roughly independent of bias for electrons, but varies significantly with bias for holes.