Morphology-Dependent Magnetism in Nanographene: Beyond Nanoribbons
- Jiri Tucek, Piotr Blonski, Ondrej Malina, Martin Pumera, Chun Kiang Chua, Michal Otyepka*, Radek Zboril*
Imprinting self-sustainable magnetic features into graphene has recently generated much interest owing to its potential application in spintronics. Several strategies for imprinting magnetic features into graphene are proposed theoretically. However, only a few of them are realized experimentally. Here, the first scalable synthesis of magnetic graphene nanoplatelets with diverse morphologies, including nanoribbons and triangular, pentagonal, hexagonal, and other polyhedral shapes, is reported. This material enters the ferromagnetic regime at a temperature of approximate to 37 K with magnetization approaching approximate to 0.45 emu g(-1) under high external magnetic fields. Theoretical calculations are used to explain this sort of morphology-driven magnetism of graphene nanoplatelets, which emerges from the synergistic effects of the size, geometry of nanographenes, edge terminations, and angle between adjacent edges. In addition, they suggest a new way for preparing magnetically ordered graphene nanoplatelets with a higher transition temperature. In this respect, triangular motifs with zigzag edges represent the most promising morphology of graphene nanoplatelets, which can remain magnetically ordered up to approximate to 107 K. Based on these challenging results, further tuning of the size and morphology in spatially confined nanographenes combined with doping and sp(3) functionalization will enable the preparation of magnetically ordered half-metallic carbon sustainable up to room temperature, thus opening new opportunities in spintronics.