Rhombic Fe2O3 lumps doping hollow ZnFe2O4 spheres through oxidative decomposition process implanted into graphene conductive network with superior electromagnetic wave absorption properties

Conductor-dielectric-magnetic multicomponent coordination composites with rhombic Fe2O3 lumps doping hollow ZnFe2O4 spheres through oxidative decomposition process implanted into graphene conductive network (hollow ZnFe2O4 spheres/rhombic Fe2O3 lumps/rGO composites) were successfully constructed by a facile method. The countless hollow ZnFe2O4 spheres were compactly attached to the curled-paper rGO and larger sized-rhombic Fe2O3 lumps were relatively dispersed. Among, the hollow structure of ZnFe2O4 spheres could attenuate the electromagnetic wave by multiple reflections and scatterings. Intriguingly, hollow ZnFe2O4 spheres reacted with GO to form intermediate rhombic Fe2O3 lump products, which ameliorated the hetero-interfaces structure and helped to improve impedance matching by weakening the strong magnetic ZnFe2O4 (Ms = 91.2 emu/g) and high conductive rGO after the introduction of weakly magnetic Fe2O3 semiconductor. Moreover, all three components could induce dielectric polarization losses, such as multilayer or dipole polarization. Therefore, the maximum absorption of ternary composites was up to -64.3 dB at 7 GHz and 3.4 mm, simultaneously, and a bandwidth exceeding-10 dB was 4.2 GHz at 1.7 mm. Meanwhile, with a thin thickness range of 1.5-5 mm, the absorption bandwidth below -10 dB was from 2 to 18 GHz which occupied for 91.5% of whole study frequency range. These results provided a new approach and reference for the design and property regulation of electromagnetic materials at electronic communications, aerospace and military radar flied.