ZnFe2O4@Polypyrrole nanocomposites as an efficient broadband electromagnetic wave absorber at 2–40 GHz

Abstract In this work, polypyrrole-coated ZnFe 2 O 4 (ZnFe 2 O 4 @PPy) nanocomposites were successfully synthesized via a simple in-situ polymerization process, then evaluated as electromagnetic wave (EMW) absorbers over the 2–40 GHz frequency range. The ZnFe 2 O 4 @PPy nanocomposites exhibited excellent EMW absorption properties, including very low reflection losses (−42.31 dB at 30.24 GHz and a thickness of 2.5 mm) and a broad absorption bandwidth of 28.20 GHz (from 9.66 to 37.86 GHz). The EMW absorption properties of the ZnFe 2 O 4 @PPy nanocomposites could be adjusted by changing the PPy shell thickness and also the thickness of the absorber (1–2.5 mm). The excellent microwave absorption performance of the ZnFe 2 O 4 @PPy nanocomposites is attributable to the synergistic effects of magnetic losses (ZnFe 2 O 4 nanoparticles), dielectric losses (ZnFe 2 O 4 and PPy) and interfacial relaxation losses at ZnFe 2 O 4 -PPy interfaces.