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arXiv · 2101.09946

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

R. O. M. Aboljadayel·C. J. Kinane·C. A. F. Vaz·D. M. Love·R. S. Weatherup·P. Braeuninger-Weimer·M. -B. Martin·A. Ionescu·A. J. Caruana·T. R. Charlton·J. Llandro·P. M. S. Monteiro·C. H. W. Barnes·S. Hofmann·S. Langridge
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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 confirms the presence of a magnetic signal in the graphene layer and the sum rules give a magnetic moment of up to $\sim\,0.47\,\mu$_B/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 $\sim$ 0.53 $\mu$_B/C atom at 10 K for rotated graphene and $\sim$ 0.38 $\mu$_B/C atom at 10 K for epitaxial graphene. Additional PNR measurements on graphene grown on a non-magnetic Ni_9Mo_1 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-3d hybridization.

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R. O. M. Aboljadayel, C. J. Kinane, C. A. F. Vaz, D. M. Love, R. S. Weatherup, P. Braeuninger-Weimer, M. -B. Martin, A. Ionescu, A. J. Caruana, T. R. Charlton, J. Llandro, P. M. S. Monteiro, C. H. W. Barnes, S. Hofmann, S. Langridge. 2021-01-25. Determining the Proximity Effect Induced Magnetic Moment in Graphene by Polarized Neutron Reflectivity and X-ray Magnetic Circular Dichroism. https://doi.org/10.1021/acsami.2c02840

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