Gate control of spin transport in multilayer graphene

We experimentally studied the gate voltage dependence of spin transport in multilayer graphene (MLG) using the nonlocal spin detection technique. We found that the spin signal is a monotonically decreasing linear function of the resistance of MLG, which is characteristic of the intermediate interfacial transparency between the MLG and the ferromagnetic electrodes (Co). The linear relation indicates a large spin relaxation length significantly exceeding 8 mu m. This shows the superiority of MLG for the utilization of the graphite-based spintronic devices. (c) 2008 American Institute of Physics.