Observation of the predicted potential barrier at the graphene/transition metal interface

To verify the prediction of a potential barrier (∼0.4 eV) as a result of charge transfer from a transition metal (TM) to graphene at the graphene/TM interface, in the present work Fe atoms are intercalated in between the few-layer graphene. A diode-like behavior with cut-in voltage (0.41 V-0.65 V) and rectification ratio 11 at 1.7 V is observed depending on the Fe concentration. The cut-in voltage decreases with an increase in both temperature and magnetic field because of better charge sharing across the covalent bond formed between Fe and graphene. This tuning of charge sharing under a magnetic field exhibits a remarkable effect of the magneto-dielectric property with a 2597% change in dielectric permittivity at 1.8 T. We believe that the material exhibiting diode-like behavior with a large rectification ratio and a giant magneto-dielectric effect has potential applications in magneto-electronic devices.