Structural, electrical, and magnetic properties of polypyrrole–Zn0.5Ni0.45Mn0.05Fe2O4 nanocomposites prepared by in situ chemical polymerization

Abstract

Polypyrrole–Zn0.5Ni0.45Mn0.05Fe2O4 nanocomposites are conducting polymer-ferrites with useful properties and new functions. The ferrite and polypyrrole–ferrite nanocomposites were synthesized by wow sol gel and in situ chemical polymerization respectively. The structures, morphology, electrical and magnetic properties of the samples were characterized by various instruments. The results of X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectra and field emission scanning electron microscopy (FE-SEM) showed the presence of the two intended phases. FE-SEM results show that phase separation was found to increase with increase of ferrite contents. The crystallite size measured by XRD was found to be in the range 40.9–88.6 nm. Possible bonding effect between metal cations and Polypyrrole (PPy) made the electronic density of the polymer chain reduce and hence resulted in the decrease of the conductivity. The room temperature dielectric measurements were performed in the frequency range 0.1 kHz–1 MHz. The dielectric constant followed the Maxwell–Wagner interfacial polarization. The frequency dependent conductivity obeyed a power law of frequency. Incorporation of ferrites in the conducting polypyrrol matrix leads to higher values of dielectric constant and dielectric loss. The loss tangent was found to have high values for composite materials as compared to pure samples. Under applied magnetic field, the Hysteresis measurements revealed that the saturation magnetization increased with increase in ferrite content. Anisotropy constant K values showed that grains were not single domains and anisotropy contribution is not uniaxial. In general the different variety of the results obtained by just changing the relative percentage of PPy–Zn,Ni,Mn ferrites nanocomposites, made the present studied samples to be useful in radiation absorption and shielding applications.