Synthesis and Electromagnetic and Microwave Absorption Properties of Monodispersive Fe₃O₄/α-Fe₂O₃ Composites

Fe₃O₄/α-F_e2O₃ composites were synthesized by a one-step method. The composition and their performances were modified by adjusting the concentration of Fe³⁺ (FeCl₃·6H₂O) in the precursor solution, effectively. Compared with single-phase Fe₃O₄ and Fe₂O₃, the effective microwave absorbing ability of Fe₃O₄/α-Fe₂O₃ composites is much widened in the range 1-18 GHz, which could stem from the enhanced dipolar polarization and interfacial polarization due to lattice dislocations at the interface of Fe₃O₄/α-Fe₂O₃. The minimum reflection loss (RL) of Fe₃O₄/α-Fe₂O₃ composites reaches about -43.1 dB at a thickness of 2.0 mm, with the effective absorption band reaching 3.4 GHz (9.8-13.2 GHz). In the thickness of 1.5-3.2 mm, the width of the RL reaches 9.9 GHz (3.5-13.4 GHz). The results demonstrate that Fe₃O₄/α-Fe₂O₃ composites could be a candidate to be used as absorbers with the microwave absorption band much widened.