Determining the Proximity Effect-Induced Magnetic Moment in Graphene by Polarized Neutron Reflectivity and X-ray Magnetic Circular Dichroism

Razan O.M. Aboljadayel, Christy J. Kinane, Carlos A.F. Vaz, David M. Love, Robert S. Weatherup, Philipp Braeuninger-Weimer, Marie Blandine Martin, Adrian Ionescu, Andrew J. Caruana, Timothy R. Charlton, Justin Llandro, Pedro M.S. Monteiro, Crispin H.W. Barnes, Stephan Hofmann, Sean Langridge

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

We report the magnitude of the induced magnetic moment in CVD-grown epitaxial and rotated-domain graphene in proximity with a ferromagnetic Ni film, using polarized neutron reflectivity (PNR) and X-ray magnetic circular dichroism (XMCD). The XMCD spectra at the C K-edge confirm the presence of a magnetic signal in the graphene layer, and the sum rules give a magnetic moment of up to ∼0.47 μB/C atom induced in the graphene layer. For a more precise estimation, we conducted PNR measurements. The PNR results indicate an induced magnetic moment of ∼0.41 μB/C atom at 10 K for epitaxial and rotated-domain graphene. Additional PNR measurements on graphene grown on a nonmagnetic Ni9Mo1 substrate, where no magnetic moment in graphene is measured, suggest that the origin of the induced magnetic moment is due to the opening of the graphene’s Dirac cone as a result of the strong C pz-Ni 3d hybridization.

Original languageEnglish
Pages (from-to)22367-22376
Number of pages10
JournalACS Applied Materials and Interfaces
Volume15
Issue number18
DOIs
StatePublished - May 10 2023
Externally publishedYes

Funding

We would like to thank the ISIS Neutron and Muon Source for the provision of beam time (RB1510330 and RB1610424). The data are available at DOIs 10.5286/ISIS.E.RB1510330 and 10.5286/ISIS.E.RB1610424. Part of this work was performed at the Surface and Interface Microscopy (SIM) beamline of the Swiss Light Source (SLS), Paul Scherrer Institut (PSI), Villigen, Switzerland. We would also like to thank the reviewer for their astute overview of the fitting, which was invaluable in improving the fits and tightening up the conclusions. Other data presented in this study are available from the corresponding author upon request.

Keywords

  • PNR
  • XMCD
  • graphene
  • heterostructure
  • magnetism

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