Optimised polyaniline–cadmium ferrite nanocomposite: synthesis, characterisation and alternating current response

In the present work, optimised polyaniline–cadmium ferrite (PANI–CdFe₂O₄) composite was prepared by chemical polymerization method. Comparative structural and morphological studies of PANI, CdFe₂O₄ and the composite were carried out by Fourier transform infrared spectroscopy, X-ray diffraction study and scanning electron microscopy. Highly crystalline nature of the composite composed of nanosized particles was confirmed by transmission electron microscopy studies. The dielectric loss tangent at room temperature for PANI, CdFe₂O₄ and the composite were investigated in the frequency range 50 Hz–5 MHz. The Maxwell–Wagner type polarisation in PANI and CdFe₂O₄ was confirmed by the decrease in their dielectric loss tangents with increasing frequency. But for the composite, a loss tangent peak due to relaxation losses implying resonance between hopping frequency of charge carriers and applied alternating current electric field was obtained. Debye type single relaxation in PANI and the distribution of relaxation in the composite were confirmed by their respective complex plane impedance plots and the plots simulated, equivalent RC network predicted and numerical values of R and C determined.