Tunneling Spin Injection into Single Layer Graphene (Supplementary Information)

TL;DR

This paper demonstrates successful tunneling spin injection into single layer graphene using TiO2 seeded MgO barriers, achieving record non-local magnetoresistance at room temperature and highlighting the importance of tunnel barriers in spin transport studies.

Contribution

It introduces a novel tunneling contact method for spin injection into graphene, achieving the largest non-local magnetoresistance and providing insights into contact effects on spin relaxation.

Findings

Record non-local magnetoresistance of 130 Ω at room temperature.

Contrasting behaviors in spin transport regimes predicted by drift-diffusion theory.

Tunnel barriers reduce contact-induced spin relaxation.

Abstract

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.