Giant magnetoresistance in ultra-small Graphene based devices

TL;DR

This paper demonstrates that ultra-small graphene devices can achieve 100% magnetoresistance by switching between insulating and conducting states under magnetic fields, enabling potential carbon-based spintronic applications.

Contribution

The study introduces a graphene-based device exhibiting giant magnetoresistance through spin-polarized transport calculations, highlighting a novel all-carbon spintronic component.

Findings

Achieves 100% magnetoresistance in graphene devices.

Magnetoresistance is significant at liquid nitrogen temperature with 10 Tesla.

Device switches from insulating to conducting under magnetic field.

Abstract

By computing spin-polarized electronic transport across a finite zigzag graphene ribbon bridging two metallic graphene electrodes, we demonstrate, as a proof of principle, that devices featuring 100% magnetoresistance can be built entirely out of carbon. In the ground state a short zig-zag ribbon is an antiferromagnetic insulator which, when connecting two metallic electrodes, acts as a tunnel barrier that suppresses the conductance. Application of a magnetic field turns the ribbon ferromagnetic and conducting, increasing dramatically the current between electrodes. We predict large magnetoresistance in this system at liquid nitrogen temperature and 10 Tesla or at liquid helium temperature and 300 Gauss.