▎ 摘　　要

We report on the electrical injection and detection of spin accumulation in trilayer-graphene/MgO/Permalloy lateral spin-valve (LSV) structure. Non-local spin valve signal is clearly observed in the LSV, indicating that spin coherence extends underneath all ferromagnetic contacts. We also show that low-resistivity graphene/MgO/Py junctions enable efficient spin injection and detection in LSV with high applied current density, which leads to large spin accumulation of 120 mu V at room temperature. A spin diffusion length of 1.5 mu m was obtained for the injector-detector separation dependence of spin valve signal measurements carried out at room temperature, while at T = 10 K, the diffusion length increases to 2.3 mu m. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4776699]