Microwave absorption performance of hierarchical structured composites of greigite and reduced graphene oxide

The greigite (Fe3S4)/reduced graphene oxide (RGO) hierarchical structural composites (F-R) with the Fe3S4 nanoparticles attached to the RGO layers were successfully prepared via a simple one-pot solvothermal method. The microwave absorption properties were evaluated by calculating the reflection loss (RL) values. The results show that the RGO content and the filler loading of composites in paraffin mixture are very critical to the microwave absorption properties because they can improve the electromagnetic parameters. Sample F-R-3 presents the best microwave absorption capacity, in which an optimum RL value of - 62.3 dB and an effective absorption bandwidth (EAB, RL value < - 10 dB) of 3.04 GHz (14.96-18 GHz) can be obtained when the matching thickness is only 1.29 mm. Meanwhile, the widest EAB reaches 4.08 GHz (13.92-18 GHz) at the matching thickness of only 1.37 mm. Impressively, when the matching thickness is in the range of 1.2-5.5 mm, all RL peaks are below - 20 dB, and the EAB can be 14.98 GHz (3.02-18 GHz), covering the whole C, X and Ku bands. The distinguished absorption property is mainly ascribed to the combined effect of strong loss ability and good impedance matching. Apparently, the F-R composite with strong absorption ability, thin thickness and wide EAB is suitable for the efficient microwave absorber.