Enhanced microwave absorption properties of rod-shaped Fe₂O₃/Fe₃O₄/MWCNTs composites

A novel type of composite absorber, i.e. Fe₂O₃/Fe₃O₄/MWCNTs composites (0%, 1.7% and 5% MWCNTs), with microwave absorption properties was successfully fabricated by a facile hydrothermal method. The prepared α-Fe₂O₃/Fe₃O₄ nanoparticles displayed rod-shaped morphology. The complex permittivity and permeability of the Fe₂O₃/Fe₃O₄/MWCNTs composites distinctly increased, furthermore, with the introduction of MWCNTs, the Fe₂O₃/Fe₃O₄/MWCNTs composites exhibited fine microwave absorption performance with strong absorption and wide absorption band. In particular, for Fe₂O₃/Fe₃O₄/1.7% MWCNTs composite with an absorber thickness of 2.5 mm, the reflection loss (RL) reached a minimum of −44.1 dB at 10.4 GHz and the effective absorption bandwidth (RL<−10 dB) covered 3.3 GHz. The enhanced microwave absorption performance of the Fe₂O₃/Fe₃O₄/MWCNTs composites was attributed to the high dielectric loss and improved impedance matching which was closely related to the rod-shaped morphology of Fe₂O₃, Fe₃O₄ and the introduction of MWCNTs.