Preparation and electromagnetic properties of BaFe₁₂O ₁₉-Ni_0.8Zn_0.2Fe₂O ₄/polypyrrole composite film

BaFe₁₂O₁₉-Ni_0.8Zn_0.2Fe ₂O₄/Polypyrrole composite film [including three doping acids, dodecyl benzene sulfonic acid (DBSA), camphor sulfonic acid (CSA) and p-toluenesulfonic acid (TSA)] was prepared by sol-gel method and in situ chemical oxidative polymerization. The structure, morphologies, conductivities, magnetic properties and microwave absorption properties of the composite film were characterized by using XRD, FESEM, FTIR, Four-probe tester, VSM and Vector network analyzer. The results show that the conductivity of acid-doped Polypyrrole composite film is higher than that of pure Polypyrrole composite film. The saturation magnetization (M_s) and remanent magnetization (M_r) of the composite film are lower than those of BaFe ₁₂O₁₉-Ni_0.8Zn_0.2Fe₂O ₄ film. However, the electromagnetic properties are in the contrary. The microwave absorption properties of the composite film are much better than those of BaFe₁₂O₁₉-Ni_0.8Zn_0.2Fe ₂O₄, which mainly depends on the increasing of the dielectric loss. A minimum reflection loss of the DBSA-doped composite film is -17.6 dB at 9.3 GHz with the thickness at 3.0 mm.