Room-temperature Ferromagnetic All-carbon Films Based on Reduced Graphene Oxide

Nano carbon materials with ferromagnetism have significant application value in fields such as spintronics, biomedical imaging, electrodes, and dye adsorption. Graphene derivatives graphene oxide (GO) and reduced graphene oxide (rGO) exhibit excellent physical and chemical properties, presenting a room temperature ferromagnetic ordered structure. In order to achieve large-scale, low-cost, and stable performance of all-carbon films, a dual dimensional carbon composite strategy combining thermal reduction was adopted to prepare composite films of micro reduced graphene oxide fibers (rGOFs) and nano scale rGO sheets, and the ferromagnetic mechanism of all-carbon films was explained partially. This work prepared rGO-rGOFs all-carbon composite films with different masses of rGOFs, focusing on the ferromagnetic mechanism and magnetoresistance effect of the materials. The research results find that introducing a certain amount of rGOFs can increase the room temperature saturation magnetization of rGO films from 0.0083 to 0.0960 A<middle dot>m2<middle dot>kg-1. Enhancement of the ferromagnetism is achieved through combined effect of vacancy type defects and sp3(C-C) states in carbon film. Interference of metal impurities in the sample, which may affect the saturation magnetization, is eliminated by inductively coupled plasma mass spectrometry. In addition, at room temperature and +/- 1 T magnetic field, the magnetoresistance (MR) curve shows MR value of sample is negative. By regulating the surface topology and sp3(C-C)/sp2(C=C) ratio of the material, the room temperature saturation magnetization has been improved to a higher extent. In short, this new type of all-carbon thin film is expected to be applied to spintronic devices and biomedical fields in the near future.