▎ 摘　　要

We report the fabrication of the La2/3Sr1/3MnO3 (LSMO)/graphene/Co sandwich structures employing single-layer graphene as the interlayer. Appreciable negative spin valve signals were observed from room temperature to 5 K. We find that the devices demonstrate nonlinear current-voltage (I-V) characteristics around room temperature, indicating that the tunneling effect is dominated rather than the Ohmic property. However, I-V curves exhibit evident linear behavior at low temperatures, which reveal the Ohmic characteristic. The vertical graphene spin valves using LSMO electrode have potential application in memory storage and logic operation.