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 ≈37 K with magnetization approaching ≈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 ≈107 K. Based on these challenging results, further tuning of the size and morphology in spatially confined nanographenes combined with doping and sp3 functionalization will enable the preparation of magnetically ordered half-metallic carbon sustainable up to room temperature, thus opening new opportunities in spintronics.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the support from the Ministry of Education, Youth and Sports of the Czech Republic under Project No. LO1305, the support by the Operational Programme Research, Development and Education—European Regional Development Fund, Project No. CZ.02.1.01/0.0/0.0/16_019/0000754 of the Ministry of Education, Youth and Sports of the Czech Republic, and the assistance provided by the Research Infrastructure NanoEnviCz supported by the Ministry of Education, Youth and Sports of the Czech Republic under Project No. LM2015073. P.B. acknowledges Palacký University institutional support. M.O. acknowledges funding from an ERC Consolidator grant (H2020) No. 683024. J.T. thanks Dr. Michaela Tucˇková for assistance with design and optimization of measuring protocols for magnetization measurements (supported by the Martina Roeselová Memorial Fellowship). The authors thank Dr. Ariana Opletalová, Dr. Martin Petr, and Dr. Ondrˇej Tomanec (all from the Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University in Olomouc, Czech Republic) for Raman spectroscopy, XPS, and HRTEM measurements, respectively.
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics