Preparation and characterization of ferromagnetic carbon nano-particles based on the graphene edge states

铁磁性碳纳米粒子可以通过在含氢的大气压Ar中高温激光汽化碳粉末来制备。然而，我们不能排除这种铁磁性源于碳粉中含有100ppm量级的杂质铁的可能性。事实上，发现当杂质铁含量低于10ppm时，铁磁特性消失。另一方面，我们成功地捕捉到了非常微弱的信号，这可能是基于高度氮掺杂的石墨烯薄膜中形成的锯齿形边缘。这将为验证碳的固有铁磁性提供线索。

Ferromagnetic carbon nano-particles can be prepared by the laser vaporization of a carbon powder in a hydrogen containing atmospheric pressure of Ar at high temperature. However, we cannot exclude a possibility of that such ferromagnetism is originated in the impurity iron containing in the carbon powder with the order 100 ppm. As a fact, it was found that the ferromagnetic feature disappeared when the impurity iron level lowered less than 10 ppm. On the other hand, we have succeeded to catch a very weak signal possibly based on the zig-zag edges formed in a highly nitrogen doped graphene film. This will be a clue for verifying the intrinsic carbon ferromagnetism.