Small magnetic nanoparticles decorating reduced graphene oxides to tune the electromagnetic attenuation capacity

High efficiency and lightweight are key factors for microwave absorption materials. Searching for the above necessary features is still a great challenge. Herein, we deposited small magnetic nickel ferrite nanoparticles on reduced graphene oxide nanosheets uniformly (NiFe2O4/r-GO) using a facile one-pot hydrothermal method with free of chemical agents, and investigated their permittivity, permeability and microwave absorption. Notably, we find an effective strategy for tuning microwave attenuation by the synergistic effect of dielectric and magnetic loss, which originates from inducing multiple relaxations and multiple resonances. The best impedance matching of NiFe2O4/r-GO was sought out. The minimum reflection loss (RL) can reach -42 dB with a broad bandwidth (RL <= -10 dB) of 5.3 GHz. Meanwhile, the multiple regions endow the absorbers with selectivity for efficient absorption. Our results demonstrate that the as-prepared NiFe2O4/r-GO is a promising candidate for application in communication devices, high speed processors, information security, electronic countermeasures and electromagnetic interference shielding.