Facile synthesis of CoFe₂O₄@SiO₂ nanoparticles anchored on reduced graphene oxide for highly efficient electromagnetic wave absorption

In this study, a ternary composite material composed of CoFe₂O₄@SiO₂ nanospheres and reduced graphene oxide (RGO) was successfully synthesized through a facile route. The composites exhibited a layered "sandwich" structure, where CoFe₂O₄@SiO₂ nanospheres were anchored onto the surface of RGO nanosheets. The microstructure and electromagnetic wave absorption properties of the synthesized CoFe₂O₄@SiO₂/RGO were systematically investigated. Results revealed that the composites possessed excellent electromagnetic wave absorption performance, with a minimum reflection loss (RL) of -27.7 dB at 13.02 GHz for a thickness of 1.8 mm. Furthermore, the composites exhibited a broad absorption bandwidth of up to 14.52 GHz (3.48-18 GHz) with reflection losses less than -10 dB over a thickness range of 1.5 to 5.0 mm, covering the S-Ku band. The enhanced absorption performance could be attributed to the optimized impedance matching and synergistic electromagnetic loss mechanisms. The CoFe₂O₄@SiO₂/RGO composites demonstrated balanced dielectric and magnetic loss, enabled by the effective interaction of electromagnetic parameters. These results indicate that the developed composites provide a promising candidate for high-performance microwave absorbing materials with lightweight, strong absorption, and broad bandwidth characteristics, potentially applicable in military stealth technology, electromagnetic compatibility enhancement, and ecological protection.