Synthesis and enhanced electromagnetic absorption properties of polypyrrole-BaFe₁₂O₁₉/Ni_0.8Zn _0.2Fe₂O₄ on graphene nanosheet

The polypyrrole(PPy)-BaFe₁₂O₁₉/Ni _0.8Zn_0.2Fe₂O₄ was produced by an in situ polymerization, and then PPy-BaFe₁₂O₁₉/Ni _0.8Zn_0.2Fe₂O₄-graphene composites were prepared by a deoxidation technique. The structures, morphology and electromagnetic properties of the samples were characterized by various instruments. Results show that PPy-BaFe₁₂O₁₉/Ni _0.8Zn_0.2Fe₂O₄ nanoparticles are dispersed on the graphene sheets. The saturation magnetization of the composites decrease from 33.93 to 26.93 emu/g with increasing the contents of graphene. However, the conductivities of the composites increase from 0.33 to 1.32 S/cm. Measurement of electromagnetic parameters indicates the reflection loss of the composites with 10% graphene is below -10 dB at 7.8-11.6 GHz and its maximum loss value is -25.5 dB at 9.8 GHz. The bandwidth corresponding to the reflection loss below -10 dB is 3.8 GHz.