Spin injection into multilayer graphene from highly spin-polarized Co2FeSi Heusler alloy

TL;DR

This paper reports successful electrical spin injection into multilayer graphene using a highly spin-polarized Co2FeSi Heusler alloy electrode, achieving the largest non-local magnetoresistance signal reported in graphene devices.

Contribution

It demonstrates a novel transfer method for fabricating high-quality CFS electrodes on graphene, enabling efficient spin injection and record non-local MR in graphene-based spintronic devices.

Findings

Record non-local MR of 430 ohm in graphene devices

Successful spin injection from CFS electrodes into multilayer graphene

Development of a polymer-based transfer method for high-quality CFS contacts

Abstract

We demonstrate electrical spin injection into multilayer graphene (MLG) in a lateral spin valve device from a highly spin-polarized Co2FeSi (CFS) Huesler electrode. Exfoliated MLG was transferred onto pre-patterned epitaxial CFS wires grown on an Si(111) substrate by a polymer-based transfer method. This method enabled us to fabricate multiple single-crystal CFS electrodes in contact with MLG. Electrical spin injection from CFS to MLG was detected through non-local magnetoresistance (MR) measurement. A non-local spin signal of 430 ohm was observed; this is the largest value among all reported non-local MR values in graphene-based devices.