Magnetic properties of graphene oxide decorated with magnetite nanoparticles

Abstract

The present work reports a study on the magnetic properties of graphene oxide decorated with magnetite nanoparticles (GO·Fe3O4), at room temperature. A total of ten samples were prepared via co-precipitation method, controlling the magnetite incorporation on the GO surface. Magnetic characterization was performed using a vibrating sample magnetometer. Transmission electron microscopy and X-ray diffraction were employed for structural investigation. All systems presented magnetisation loops that resemble a Langevin function at the high field region, but also have non-zero coercivity and remanent magnetisation. These features are attributed to the size distribution of the magnetic nanoparticles. A portion of the magnetite particles is small enough to present superparamagnetic behaviour, while the bigger ones are ferrimagnetic. Using the in-field δMR interaction-plots technique, it was observed that demagnetising interactions are predominant. Magnetic parameters like coercivity and remanent magnetisation, however, are mainly governed by average particle size, and not by such interactions.