▎ 摘　　要

We present an enhancement in spin injection from ferromagnet to multilayer graphene through the introduction of a thin Cu interfacial layer at the metal-graphene interface. A nonlocal magnetoresistance of 286m Omega and a corresponding spin-injection efficiency of 2.46% have been obtained which are among the highest values reported so far for metal-contacted graphene spin-valve devices. The enhancement of spin-injection is attributed to a non-ohmic contact between Cu and graphene, as revealed by the temperature-dependent I-V and differential conductance measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4733729]