Spin-dependent properties of single-layer graphene (SLG) have been studied by non-local spin valve measurements at room temperature. Gate voltage dependence shows that the non-local magnetoresistance (MR) is proportional to the conductivity of the SLG, which is the predicted behavior for transparent ferromagnetic/nonmagnetic contacts. While the electron and hole bands in SLG are symmetric, gate voltage and 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.
@article{arxiv.0903.1130,
title = {Electron-Hole Asymmetry of Spin Injection and Transport in Single-Layer Graphene},
author = {Wei Han and W. H. Wang and K. Pi and K. M. McCreary and W. Bao and Yan Li and F. Miao and C. N. Lau and R. K. Kawakami},
journal= {arXiv preprint arXiv:0903.1130},
year = {2010}
}