Large room temperature spin-to-charge conversion signals in a few-layer graphene/Pt lateral heterostructure

Wenjing Yan,Mário Ribeiro,Luis E Hueso,Edurne Sagasta,Fèlix Casanova,Yasuhiro Niimi

doi:10.1038/s41467-017-00563-y

Wenjing Yan, Mário Ribeiro + Show 4 more

Open Access

https://doi.org/10.1038/s41467-017-00563-y

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Journal: Nature Communications	Publication Date: Sep 22, 2017
Citations: 57	License type: open-access

Affiliation: CIC nanoGUNE, Ikerbasque, Osaka University

Abstract

Electrical generation and detection of pure spin currents without the need of magnetic materials are key elements for the realization of full electrically controlled spintronic devices. In this framework, achieving a large spin-to-charge conversion signal is crucial, as considerable outputs are needed for plausible applications. Unfortunately, the values obtained so far have been rather low. Here we exploit the spin Hall effect by using Pt, a non-magnetic metal with strong spin-orbit coupling, to generate and detect pure spin currents in a few-layer graphene channel. Furthermore, the outstanding properties of graphene, with long-distance spin transport and higher electrical resistivity than metals, allow us to achieve in our graphene/Pt lateral heterostructures the largest spin-to-charge output voltage at room temperature reported so far in the literature. Our approach opens up exciting opportunities towards the implementation of spin-orbit-based logic circuits and all electrical control of spin information without magnetic field.

Highlights

Electrical generation and detection of pure spin currents without the need of magnetic materials are key elements for the realization of full electrically controlled spintronic devices
While advances have been made in the electrical control of spin transport[1,2,3,4], new approaches that allow electrical generation or detection of pure spin currents without using ferromagnetic materials (FM) as the spin source are being developed[5,6,7,8]
In the emerging field of spin orbitronics[9, 10], by uniquely exploiting the spin-orbit coupling (SOC) in non-magnetic materials, spin-to-charge current conversions have been realized using the spin Hall effect (SHE)[11,12,13], the Rashba–Edelstein effect[14, 15], or the spin-momentum locking in topological insulators[16, 17]

Summary

Introduction

Electrical generation and detection of pure spin currents without the need of magnetic materials are key elements for the realization of full electrically controlled spintronic devices In this framework, achieving a large spin-to-charge conversion signal is crucial, as considerable outputs are needed for plausible applications. We exploit the spin Hall effect by using Pt, a non-magnetic metal with strong spin-orbit coupling, to generate and detect pure spin currents in a few-layer graphene channel. A clear route to enhance θSH of Pt has been unveiled[21] Another path that has been explored to maximize the output voltage is the use of higher resistive spin Hall materials, the potential enhancement is counteracted by the increased shunting of the induced charge current in the less resistive spin transport material, usually Cu or Ag8. Our concept of using charge-to-spin conversion to inject a spin current and spin-to-charge conversion to detect a spin currents in graphene-based devices could open future applications of all electrical control of spin information without magnetic field

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