Synthesis of ferromagnetic sandwich FeCo@graphene@PPy and enhanced electromagnetic wave absorption properties

In this work, a ternary sandwich structure of FeCo@RGO@PPy was successfully fabricated by a three-step method. The structure and morphology of samples were characterized by XRD, FTIR, XPS, TEM and FESEM. TEM and FESEM images indicate that FeCo particles with a size of about 20-40 nm are grown on surface of RGO@PPy, between RGO and PPy. VSM results reveal that FeCo@RGO@PPy composite possesses a ferromagnetic behavior, and the electromagnetic wave absorption properties of its were investigated at 2-18 GHz. The maximum reflection loss of ternary composite can reach −40.7 dB at 4.5 GHz and the absorption bandwidth with the reflection loss exceeding −10 dB is 5.7 GHz (3.1-6 GHz and 12.8-15.6 GHz) with the thickness of 2.5 mm, which shows an improved microwave absorption properties compared with FeCo. The microwave absorption mechanisms were also investigated in detail.