Polypyrrole and its nanocomposites with Zn_0.5Ni_0.4Cr_0.1Fe₂O₄ ferrite: preparation and electromagnetic properties

Polypyrrole (PPy)–Zn_0.5Ni_0.4Cr_0.1Fe₂O₄ core–shell nanocomposites have been fabricated by in situ chemical polymerization of pyrrole in the presence of ZnNiCr ferrite nanoparticles. The samples were characterized by X-ray diffractometer, FTIR spectroscopy, TGA/DTA analysis and field emission scanning electron microscopy (FE-SEM). Dielectric and Magnetic properties were investigated by using impedance analyzer and vibrating sample magnetometer respectively. The results of XRD, FTIR showed the presence of the two intended phases. FE-SEM results confirm the formation of core–shell structure. Possible bonding effect between metal cations and PPy resulted in the decrease of the conductivity with increase of ferrite content. Below 500 °C, the TGA and DTA results confirm the thermal stability of these samples. Incorporation of ferrites in the conducting Polypyrrole matrix leads to higher values of dielectric constant and dielectric loss. Under applied magnetic field, the Hysteresis measurements revealed that coercivity, saturation magnetization and remanance were tuned to such values that made the investigated samples suitable for microwave devices and switching applications.