Organické magnety s magnetickým uspořádáním při pokojové teplotě odvozené z sp3 funkcionalizovaného grafenu
Graphene is a unique material currently at the forefront in materials science. Despite its extraordinary electric, optical, and transport properties, pristine graphene is nonmagnetic in nature. In order to become magnetic, three key strategies were proposed to imprint magnetism into graphene, i.e., doping/substitution, sp3 functionalization, and spatial confinement. In the study published recently published in the Nature Communication journal, we present a new derivative of graphene, termed hydroxofluorographene, which, upon suitable –OH functionalization of fluorographene, shows antiferromagnetic ordering up to room temperature, i.e., a magnetic behavior not previously observed for any graphene derivative or sp-based material. At low temperature, hydroxofluorographenes with suitable F/OH ratio undergo a transition to a ferromagnetic state. The self-sustainable magnetism of hyroxofluorographenes with an appropriate stoichiometry stems from the presence of diradical motifs coupled via superexchange interaction and stabilized by –OH groups, which also mediate the coupling. The newly constructed theoretical model addresses the effect of system stoichiometry on magnetic features in an excellent agreement with experimental data. More importantly, this robust model has a universal character covering the aspects of the “defect-induced magnetism” and “diradical motif-triggered magnetism” appearing in the field of graphene magnetism depending on degree of sp3 functionalization. The developed room temperature graphene-based magnets offer a huge space for testing in potential applications in various fields including, for example, spintronics and magnetically separable nanocarriers.
Tuček, J.; Holá, K.; Bourlinos, A. B.; Błoński, P.; Bakandritsos, A.; Ugolotti, J.; Dubecký, M.; Karlický, F.; Ranc, V.; Čépe, K.; Otyepka, M.; Radek Zbořil, R. Room temperature organic magnets derived from sp3 functionalized graphene. Nat. Commun. 2017, 8, 14525. DOI: 10.1038/ncomms14525