Electromagnetic attenuation distribution in a three-dimensional amorphous carbon matrix with highly dispersed Fe/Fe3C@graphite-C nanoparticles

The dielectric-magnetic synergistic effect can be achieved by dielectric relaxation and magnetic resonances in composites of carbon materials and magnetic particles. However, there is no direct evidence demonstrating the distribution of electromagnetic energy attenuation in the microstructure of compos-ites. Herein, an amorphous carbon matrix with dispersed Fe/Fe3C@graphite-C was fabricated via a facile route. The distribution of the magnetic vector loss and electric vector loss in the hierarchical structures was revealed by numerical simulation. The content and dispersion of magnetic particles as well as the morphology of the amorphous carbon can be tuned. The 3D amorphous carbon matrix with highly dis-persed Fe/Fe3C@graphite-C nanoparticles provided the strongest absorption of-69.0 dB and an effective response bandwidth (RL <-10 dB) of 7.06 GHz. The numerical simulation revealed that the magnetic vector loss originated only from the core of Fe/Fe3C, and the electric vector loss was distributed through-out the structure, especially in the graphite-C shell, the interface between graphite-C and carbon nano-flakes, and the junction of different carbon nanoflakes. This work not only reveals the distribution of electromagnetic loss but also supports the theoretical analysis of the electromagnetic wave attenuation mechanism in composites, which provides direction for the future design of composites. (C) 2022 The Authors. Published by Elsevier Ltd.