Title: Change of magnetic behaviour of nitrogenated carbon nanotubes on chlorination/oxidation

Authors: Sekhar C. Ray; Sanyasi Sitha; P. Papakonstantinou

Addresses: Department of Physics, College of Science, Engineering and Technology, University of South Africa, Private Bag X6, Florida, 1710, Science Campus, Christiaan de Wet and Pioneer Avenue, Florida Park, Johannesburg, South Africa ' Department of Chemistry, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa ' Nanotechnology and Integrated Bio-Engineering Centre, Ulster University, Shore Road, Newtownabbey, BT37 0QB, UK

Abstract: The magnetic effects of chlorine and oxygen functionalised NCNTs have been studied. The diamagnetic behaviour of non-functionalised NCNTs changes to paramagnetic behaviour on Cl-functionalisation; on O-functionalisation NCNTs become ferromagnetic. A prominent cusp-like behaviour is observed at around ≈45 K in M_FC and M_ZFC measurements, further confirming the ferromagnetic behaviour of O-functionalised NCNTs; but Cl-functionalised NCNTs do not shows any cusp-like behaviour indicating formation of paramagnetic behaviour. The change of magnetic behaviour occurs owing to formation of different bonding with carbon/nitrogen and/or Fe-catalyst atoms that is verified with theoretical calculation. The initial computational results show that the differential bonding patterns of the Cl-functionalised and the O-functionalised NCNTs are the main cause for the different magnetic behaviour in these systems.

Keywords: magnetisation; nitrogenised CNTs; carbon nanotubes; NCNTs; oxygen; chlorine; density functional theory; DFT; magnetic behaviour; chlorination; oxidation; paramagnetism; ferromagnetism; bonding patterns; nanotechnology.

DOI: 10.1504/IJNT.2017.082456

International Journal of Nanotechnology, 2017 Vol.14 No.1/2/3/4/5/6, pp.356 - 366

Published online: 24 Feb 2017 *

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