Electrical detection of spin precession in single layer graphene spin valves with transparent contacts

Spin accumulation and spin precession in single layer graphene are studied by nonlocal spin valve measurements at room temperature. The dependence of the nonlocal magnetoresistance on electrode spacing is investigated and the results indicate a spin diffusion length of ∼1.6 μm and a spin injection/detection efficiency of 0.013. Electrical detection of the spin precession confirms that the nonlocal signal originates from spin injection and transport. Fitting of the Hanle spin precession data yields a spin relaxation time of ∼84 ps and a spin diffusion length of ∼1.5 μm, which is consistent with the value obtained through the spacing dependence.