Novel three-dimensional TiO2-Fe3O4@polypyrrole composites with tunable microwave absorption in the 2-40 GHz frequency range

Enormous research effort is currently being directed toward the development of low-cost electromagnetic wave absorbing (EMWA) materials that operate at microwave frequencies. Herein, we report the successful fabrication of novel three-dimensional TiO2-Fe3O4@Polypyrrole (T-F-P) composites with excellent microwave absorption properties between 2 and 40 GHz. By varying the thickness of the T-F-P absorber from 1.5 to 2.5 mm, an effective absorption bandwidth (EAB, reflection loss (RL) <= - 10 dB) of 28.12 GHz (11.88-40 GHz) was realized. At a thickness of 2.5 mm, the minimum reflection loss (RLmin) was - 37.49 dB (13.84 GHz) in the frequency range 2-18 GHz; - 41.30 dB (25.30 GHz) in the frequency range 18-26.5 GHz and - 42.65 dB (34.1 GHz) in the frequency range 26.5-40 GHz. Multiple reflections, interfacial polarization, conductive losses and magnetic losses all contribute to the excellent EMWA properties of the T-F-P composites.