Exploration of magnetic media modulation engineering on heterogeneous carbon spheres for optimized electromagnetic wave absorption

Abstract

Magnetic carbon spheres are promising electromagnetic wave (EMW) absorbing materials due to their strong electromagnetic coupling effect. In the present work, magnetic carbon spheres composed of N-doped carbon spheres (NCSs) with magnetic Fe and Fe3C (Fe-Fe3C) nanoparticles were synthesized and the contents of Fe nanoparticles were adjusted through dilute hydrochloric acid treatment processes. The prepared NCSs/Fe-Fe3C composites dominate excellent EMW absorption performances with an optimal reflection loss value reaching − 63.77 dB at 9.92 GHz under a matching thickness of 2.9 mm, and the effective absorption bandwidth (EAB) reaches 4.88 GHz. The excellent absorption performance can be attributed to the synergistic effect of conductance loss, polarization loss, and magnetic loss arising from the different components of the composites. Moreover, the variation of Fe contents can regulate the dielectric and magnetic permeability characteristics of NCSs/Fe-Fe3C composites, and finally balance the impedance matching and attenuation coefficient. Our results pave the way for the development of high-efficiency EMW absorbing materials and clarify the regulation mechanism of magnetic media on the absorption performances of magnetic carbon spheres.