Defect-induced, temperature-independent, tunable magnetoresistance of partially fluorinated graphene foam

The magnetoresistance (MR) of graphene is fixed under a particular magnetic field and temperature but can be further improved or controlled by introducing artificial defect states. These artificial defects can be introduced via fluorination, which is a conventional method to control the magnitude of the MR required for magnetoelectronic applications. One of the main benefits of fluorination is the defluorination, which occurs within a few days. Herein, tunable and temperature-independent magnetotransport of graphene foam (GF) is achieved using a controlled fluorination process. The magnitude of the MR decreases with the increasing fluorination time (i.e., 30, 60 and 90 min), indicating that defect-induced scattering plays a major role in the magnetotransport properties of fluorinated GF (FGF). The magnitude of the MR in the FGF specimens at room temperature (under a magnetic field strength of 5 T) was observed for three months; a particular value of the MR (FGF-30–59%, FGF-60–58%, FGF-90–37%) is observed that is higher in magnitude than that on the first day of fluorination. In this way, fluorination of GF can provide a pathway to tune the magnetotransport properties, which is very useful for magnetoelectronics devices, especially highly sensitive magnetic sensors.