Searching for magnetism in pyrrolic N-doped graphene synthesized via hydrothermal reaction

Improving the ferromagnetism property of graphene materials is particularly important for a wide range of applications such as spintronics, magnetic memory, and other electromagnetic devices. Pyrrolic nitrogen (N) doping is an effective means to enhance the ferromagnetism of graphene materials. Here we report the synthesis of N-doped graphene with 6.02 at.% doping concentration through a high-throughput hydrothermal method. X-ray photoelectron spectroscopy reveals that the pyrrolic N bonding configuration dominates over the other bonding types observed in our samples, which is in good agreement with the Raman spectroscopy and first-principle calculations. The vibrating sample magnetometer and SQUID are employed to further analyze the magnetic properties of the pyrrolic N-doped graphene. At room temperature, the sample exhibits significant ferromagnetism with a high saturation magnetic moment (1.4 × 10^-2 emu/g) among graphene materials and a narrow coercivity (181.4 Oe). Our results have not only extended the synthesis method of N-doped graphene materials but also deepened the fundamental understanding of the N doping behaviors in enhancing their magnetism.