Tunneling Spin Injection into Single Layer Graphene

Wei Han, K. Pi, K. M. McCreary, Yan Li, Jared J. I. Wong, A. G. Swartz, R. K. Kawakami

Published 2010-03-13, updated 2010-08-18Version 2

We achieve tunneling spin injection from Co into single layer graphene (SLG) using TiO2 seeded MgO barriers. A non-local magnetoresistance ({\Delta}RNL) of 130 {\Omega} is observed at room temperature, which is the largest value observed in any material. Investigating {\Delta}RNL vs. SLG conductivity from the transparent to the tunneling contact regimes demonstrates the contrasting behaviors predicted by the drift-diffusion theory of spin transport. Furthermore, tunnel barriers reduce the contact-induced spin relaxation and are therefore important for future investigations of spin relaxation in graphene.