High-performance microwave absorber based on carbon-fibers@TiO₂@SrFe₁₂O₁₉@PANI composite

In this research, we synthesized TiO₂ (S1), TiO₂@carbon-fibers (S2), TiO₂@carbon-fibers@hexaferrites (S3) and TiO₂@carbon fibers@hexaferrites@polyaniline (S4) and investigated their EM radiation absorption performance in the X-band. The phase identification analysis has proven that the prepared samples are pure and single phase without any impurity or secondary phase. The morphology analysis shows sphere-like mophology for the TiO₂ nanoparticles and rod-like morphology for the carbon-fiber, which is maintained throughout the formation of the composites. The band-gap of the S1, S2, S3 and S4 samples was calculated and respectively found to be 3.20, 2.94, 2.75 and 2.43 eV. These values of band-gap fall in the semiconducting range. The non-magnetic nature of polyaniline plays a significant role in the reduction of the values of the magnetic parameters. The S4 composites exhibit better EM radiation capabilities as compared to the S3 composite. The S4 composite as an upper layer and S3 as a lower layer was found to have a R_L value of about − 24.0 dB with a bandwidth of effective absorption of 1.7 GHz (4.2–5.9 GHz) at a combined thickness of 2 mm. The overall EM radiation absorption capability of the composites was found to be due to the dielectric loss, aside from a small contribution from magnetic losses.