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 (M_s = 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.