Strong In-Plane Magnetization and Spin Polarization in (Co0.15Fe0.85)5GeTe2/Graphene van der Waals Heterostructure Spin-Valve at Room Temperature
Journal article, 2023

Van der Waals (vdW) magnets are promising, because of their tunable magnetic properties with doping or alloy composition, where the strength of magnetic interactions, their symmetry, and magnetic anisotropy can be tuned according to the desired application. However, so far, most of the vdW magnet-based spintronic devices have been limited to cryogenic temperatures with magnetic anisotropies favoring out-of-plane or canted orientation of the magnetization. Here, we report beyond room-temperature lateral spin-valve devices with strong in-plane magnetization and spin polarization of the vdW ferromagnet (Co0.15Fe0.85)5GeTe2 (CFGT) in heterostructures with graphene. Density functional theory (DFT) calculations show that the magnitude of the anisotropy depends on the Co concentration and is caused by the substitution of Co in the outermost Fe layer. Magnetization measurements reveal the above room-temperature ferromagnetism in CFGT and clear remanence at room temperature. Heterostructures consisting of CFGT nanolayers and graphene were used to experimentally realize basic building blocks for spin valve devices, such as efficient spin injection and detection. Further analysis of spin transport and Hanle spin precession measurements reveals a strong in-plane magnetization with negative spin polarization at the interface with graphene, which is supported by the calculated spin-polarized density of states of CFGT. The in-plane magnetization of CFGT at room temperature proves its usefulness in graphene lateral spin-valve devices, thus revealing its potential application in spintronic technologies.

2D magnets

in-plane magnetization

spin-valve

van der Waals heterostructures

spin polarization

van der Waals magnet

graphene

Author

Roselle Ngaloy

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Bing Zhao

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Soheil Ershadrad

Uppsala University

Rahul Gupta

Uppsala University

Masoumeh Davoudiniya

Uppsala University

Lakhan Bainsla

Indian Institute of Technology

Lars Sjöström

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Anamul Md Hoque

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Alexei Kalaboukhov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

P Svedlindh

Uppsala University

Biplab Sanyal

Uppsala University

Saroj Prasad Dash

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

ACS Nano

1936-0851 (ISSN) 1936-086X (eISSN)

Vol. In Press

Graphene Core Project 3 (Graphene Flagship)

European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.

2D Heterostructure Non-volatile Spin Memory Technology (2DSPIN-TECH)

European Commission (EC) (EC/HE/101135853), 2023-12-01 -- 2026-11-30.

Topology and Magnetism in Novel Quantum Materials

Swedish Research Council (VR) (2018-07046), 2020-01-01 -- 2021-12-31.

Subject Categories

Other Physics Topics

Condensed Matter Physics

DOI

10.1021/acsnano.3c07462

PubMed

38330915

More information

Latest update

5/29/2024