Enhancement of Spin Injection into Graphene by Water Dipping

TL;DR

This study demonstrates that brief water dipping enhances spin injection efficiency in graphene spin valves, increasing signal magnitude and showing robustness to water exposure, thus enabling future chemical functionalization.

Contribution

It introduces a simple water dipping method to improve spin transport in graphene devices, a novel approach not previously reported.

Findings

Water dipping increases nonlocal magnetoresistance

Spin signal enhancement correlates with junction resistance

Graphene spin valves remain robust after water exposure

Abstract

We immerse single layer graphene spin valves into purified water for a short duration (<1 min) and investigate the effect on spin transport. Following water immersion, we observe an enhancement in nonlocal magnetoresistance. Additionally, the enhancement of spin signal is correlated with an increase in junction resistance, which produces an increase in spin injection efficiency. This study provides a simple way to improve the signal magnitude and establishes the robustness of graphene spin valves to water exposure, which enables future studies involving chemical functionalization in aqueous solution.