Magnetic characteristics of graphene oxide and reduced graphene oxide

Graphene oxide (GO) is 2D material made of honey comb carbon structure as backbone and decorated by oxygen functional groups in both sides. These functional groups have role to the GO properties, such as magnetic susceptibility, band gap, conductivity. There are several processes to reduce its oxygen content, such as chemical, photo and thermal reduction, resulted reduced graphene oxide (rGO). Several studies reported the magnetic properties of GO and rGO correlating with the process of synthesis and reducing oxygen contents. We report the magnetic characteristic of a commercial GO 0.5 mg/ml dispersed in H2O from Graphenia and RGO that were synthesized through thermal reduction process of GO precursor. In this process, we use oven vacuum system at 200^oC for 1 hour. All samples were prepared as GO and rGO thick films. The GO and rGO samples structure were indentified from XRD data and SQUID data for magnetic characteristics. We explored the temperature dependence of magnetic susceptibility by applying magnetic field of 500 Oe in Zero Field Cooling (ZFC) and Field Cooling (FC). The result shows different susceptibility behavior of GO and rGO samples in all wide range of temperature between 0 to 300 Kelvin. The value of magnetic susceptibility rGO is higher than that of GO and has splitting curve of ZFC and FC at low temperatures below 200 Kelvin. However, GO has the splitting curve of ZFC and FC occurred at high temperatures above 200 Kelvin.