Spin Relaxation in Weak Localization Regime in Multilayer Graphene Spin Valves

TL;DR

This study investigates how quantum interference effects in multilayer graphene influence spin relaxation, revealing that spin relaxation time and diffusion length increase significantly at low temperatures due to weak localization.

Contribution

It demonstrates that quantum interference effects in multilayer graphene can substantially extend spin relaxation times in the weak localization regime.

Findings

Spin relaxation time increases at temperatures below 70 K.

Weak localization observed from magnetoresistance measurements.

Spin diffusion length is significantly extended despite suppressed diffusion constant.

Abstract

The temperature dependence of the spin relaxation time in multilayer graphene (MLG) spin valve devices was measured using a non-local magnetoresistance (NLMR) measurement. A weak localization (WL) was observed from magnetoresistance (MR) measurements below 70 K, suggesting coherent transport of the charge carriers. Within the same temperature range, we observed a large increase in the spin relaxation time and spin diffusion length even though the diffusion constant Ds was suppressed by the WL. This demonstrated that the spin relaxation time in MLG could be significantly extended when the charge experiences quantum interference effect in the coherent charge transport regime.