Facile synthesis of Fe 3 O 4 /C composites for broadband microwave absorption properties

Abstract Rod-like and flower-like Fe 3 O 4 /C composites were successfully synthesized via a facile approach in aqueous phase. The morphologies, structures and static magnetic properties of as-prepared rod-like and flower-like Fe 3 O 4 /C composites were characterized thoroughly. The relative complex permittivity and permeability of Fe 3 O 4 /C/paraffin composites were recorded by a vector network analyzer (VNA) in the range of 1–18 GHz. The resonant-antiresonant electromagnetic behavior was observed simultaneously in both rod-like and flower-like Fe 3 O 4 /C composites. Moreover, the resonant-antiresonant behavior was explained using displacement current lag at the “core/shell” interface. The flower-like Fe 3 O 4 /C/paraffin composites show superior microwave absorption performance with minimum reflection loss ( RL ) of up to −18.73 dB at 15.37 GHz. Comparatively, the rod-like Fe 3 O 4 /C/paraffin composites have uncommon continuous trinal absorption peaks at a thickness of 2.5 mm that effectively broadens the absorption bandwidth which is from 8.0 to 13.4 GHz. Furthermore, the microwave absorption mechanism has been discussed to provide a novel design for microwave absorption materials.