Experimental and theoretical study of Tetrakis(dimethylamino)ethylene induced magnetism in otherwise nonmagnetic graphene derivatives

Abstract

Abstract Magnetic nanocarbon offers unique opportunities for future molecular spintronic applications. In such nanocarbons, emergence of magnetization mainly comes from vacancy and adatom. Present work deals with comparison of magnetic interactions in Graphene-like nanocarbons (GNCs) and graphene by adding, tetrakis (dimethyl amino) ethylene (TDAE, (CH3)2N2C = CN2(CH3)2), an organic ferromagnet. Initially, synthesized nano-carbon compounds were functionalized by ∼10 at % of TDAE. Magnetic analysis, by SQUID, showed decrease in saturation level spin density and moments/nm2 in N-doped graphene like nanocarbons (N-GNCs), while enhancement in N-doped graphene (N-graphene). The FC-ZFC study showed significant irreversibility in magnetic anisotropy that obeys anti-ferromagnetic order up to ∼20 K in graphene. Moreover, it exhibits modifications in magnetic environment of molecular carbon due to alteration in centro-symmetry and skewness of central N2C CN2 molecule, as revealed by electron spectroscopy by chemical analysis. The tendency of donor nitrogen to transfer charge is disproportionate and results in acquiring different radical states by N-GNCs (−1) and N-graphene (−2). Computational studies have been carried out for pristine graphene nanoribbons (GNRs), both armchair and zigzag and GNR with monovacancy with and without passivation. Unpassivated zigzag GNR exhibits magnetic moments at the edges but the magnetic moment is quenched at the edge atoms on adsorption of the molecule.