Magnetite-Polypyrrole Metacomposites: Dielectric Properties and Magnetoresistance Behavior

In this talk, the conductive polypyrrole (PPy) polymer nanocomposites (PNCs) reinforced with different magnetite (Fe₃O₄) nanoparticle loadings have been synthesized using a facile surface initiated polymerization (SIP) method. The morphology of the fabricated PNCs was conducted by scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM). The chemical structure of the PNCs was studied by Fourier transform infrared (FT-IR) spectroscopy, the thermal stability was performed by thermogravimetric analysis (TGA), and the crystallization structure of the PNCs was studied by X-ray diffraction (XRD). The optical properties, magnetic properties, temperature dependent resistivity, and magnetic properties of the PNCs were systematically studied. The electrical conduction mechanism was explored by the introduced Mott variable range hopping mechanism. The permittivity and magnetoresistance behaviors are investigated as well. The negative permittivity was observed at certain frequency for all the synthesized nanocomposites. The positive magnetoresistance at room temperature in the pure PPy was analyzed by the wave-function shrinkage model. The negative magnetoresistance at room temperature in the nanocomposites was interpreted by the forward interference model.