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Author Raji, Abdulrafiu T. ♦ Lombardi, Enrico B.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ACTIVATION ENERGY ♦ ATOMS ♦ COBALT ♦ ENERGY TRANSFER ♦ GRAPHENE ♦ IRRADIATION ♦ KEV RANGE 100-1000 ♦ MAGNETIC MOMENTS ♦ MAGNETIC PROPERTIES ♦ VACANCIES
Abstract We use ab initio methods to study the binding, diffusion, and magnetic properties of cobalt atom embedded in graphene vacancies. We investigate the diffusion of Co-monovacancy (Co-MV) and Co-divacancy (Co-DV) defect complexes, and determine the minimum energy path (MEP), as well as the activation energy barrier of migration. We obtained similar activation energy barriers, of ∼5.8 eV, for Co-MV and Co-DV diffusion, respectively. Our calculations also suggest that, at electron–irradiation energy of 200 keV as used in a related experiment, the maximum energy transfer to the Co atom, of approximately 9.0 eV is sufficiently high to break metal-carbon bonding. The incident electron energy is also high enough to displace graphene's carbon atoms from their lattice positions. The breaking of metal-carbon bonding and the displacement of graphene atoms may act to facilitate the migration of Co. We conclude therefore that the detrapping and diffusion of cobalt as observed experimentally is likely to be radiation-induced, similar to what has been observed for Au and Fe in electron-irradiated graphene. Furthermore, we show that Co migration in graphene is such that its magnetic moment varies along the diffusion path. The magnetic moment of Co is consistently higher in Co-DV diffusion when compared to that of Co-MV diffusion.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-21
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 118
Issue Number 11


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