Self-magnetism induced large magnetoresistance at room temperature region in graphene nanocrystallited carbon film

We report large positive magnetoresistance (MR) of over 12% at 273 K in graphene nanocrystallited pure carbon film. MR behaviors at different temperatures implied that low temperature MR was from carrier diffusive scattering and room temperature MR was from spin arrangement effect. Temperature dependences of the film resistance and magnetization recognized that as temperature decreased from 300 to 200 K, transitions occurred on the electrical transporting process from conductive mode to semi-conductive mode, and the nanocrystallited structure showed competition of ferromagnetic and antiferromagnetic interactions. The large room temperature MR was ascribed to the ferromagnetic order of spin magnetic moment arrangement at the of graphene layer edges.

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