Feromagnetismus v grafenu dopovaného atomy dusíku
Doping of the graphene lattice with nitrogen opens possibilities for tailoring the electronic properties and band gap of graphene towards its applications, e.g., in spintronics and optoelectronics. One major obstacle is development of magnetically active N-doped graphene with spin-polarized conductive behavior. Our recent work published in the Journal of the American Chemical Society reports the first example of ferromagnetic graphene achieved by controlled doping with graphitic, pyridinic, and chemisorbed nitrogen. The magnetic properties were found to depend strongly on both the nitrogen concentration and type of structural N-motifs which are generated in the host lattice. Graphenes doped below 5 at.% of nitrogen were nonmagnetic; however, once doped at 5.1 at.% of nitrogen, N-doped graphene exhib-ited transition to a ferromagnetic state at ~69 K and displayed a saturation magnetization reaching 1.09 emu/g. The theoretical results showed that magnetic effects were triggered by graphitic nitrogen, whereas pyridinic and chemisorbed nitrogen contributed much less to the overall ferromagnetic ground state. Calculations further proved the existence of exchange coupling among the paramagnetic centers mediated by the conduction electrons.
Blonski, P.; Tucek, J.; Sofer, Z.; Mazánek, V.; Petr, M.; Pumera, M.; Otyepka, M.; Zboril, R. Doping with Graphitic Nitrogen Triggers Ferromagnetism in Graphene. J. Am. Chem. Soc. 2017. DOI: 10.1021/jacs.6b12934