▎ 摘　　要

Graphene being an excellent electronic material has poor dielectric properties. In addition to unusual dielectric response (permittivity increases with frequency) due to trap induced capacitance, here we have tuned the trap states to achieve a giant value of permittivity (epsilon similar to 2214) and remarkably high magnetodielectric effect (23%) in nickel doped reduced graphene oxide (RGO). The current-voltage characteristics in the space charge limited conduction give quantitative information about these trap states. We estimate an average trap density of 1.92 x 10(22) m(-3) at room temperature. We believe that this transition metal doped RGO with tunable dielectrics has potential applications in electrical storage devices.