A seamless graphene spin valve based on proximity to van der Waals magnet Cr$_2$Ge$_2$Te$_6$

TL;DR

This paper demonstrates a seamless graphene spin valve leveraging proximity effects from the van der Waals magnet Cr$_2$Ge$_2$Te$_6$, enabling spin generation, detection, and transport with notable Hall effects.

Contribution

It introduces a novel graphene spin valve based solely on proximity effects, combining spin-orbit and magnetic exchange couplings in a seamless device.

Findings

Graphene acquires spin-orbit and magnetic exchange coupling from Cr$_2$Ge$_2$Te$_6$.

The device supports long-distance spin transport.

A sizeable anomalous Hall effect is observed.

Abstract

Pristine graphene is potentially an ideal medium to transport spin information. Proximity effects, where a neighbouring material is used to alter the properties of a material in adjacent (or proximitized) regions, can also be used in graphene to generate and detect spins by acquiring spin-orbit coupling or magnetic exchange coupling. However, the development of seamless spintronic devices that are based uniquely on proximity effects remains challenging. Here, we report a two-dimensional graphene spin valve that is enabled by proximity to the van der Waals magnet Cr$_2$Ge$_2$Te$_6$. Spin precession measurements show that graphene acquires both spin-orbit coupling and magnetic exchange coupling when interfaced with the Cr$_2$Ge$_2$Te$_6$. This leads to spin generation by both electrical spin injection and the spin Hall effect, while retaining long-distance spin transport. The simultaneous presence of spin-orbit coupling and magnetic exchange coupling also leads to a sizeable anomalous Hall effect.