A comparative study of spinel ferrites/PANI composites for high-frequency applications

The electrical and networking industries are increasingly reliant on high-frequency ferrite nanocomposites, which are produced using ferrite and a polyaniline binder. In the present study, polyaniline is prepared by in-situ, while the ferrite is synthesized by adopting sol-gel process. The X-ray diffraction (XRD) analysis showed that all the samples (except PANI) possessed spinel structure. When spinel ferrite is blended with the polymer matrix, the crystallite size increased from 19 nm to 61 nm. Combining polyaniline with ferrites leads to a decreasing trend in the dielectric parameters (epsilon', epsilon"). Hysteresis loop analysis was conducted to evaluate the materials' ferromagnetic properties. The saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) all increased as the concentration of ferrite has been increased. The direct current (dc) resistivity and activation energy of a sample containing ferrites and polyaniline also increased. These all parameters suggested that FP-4 may be suitable for high-frequency applications.Graphical AbstractIt illustrates that the dc resistivity of all samples are directly related to temperature, as heat causes charge carriers to move more. At room temperature, ferrites conduct electricity due to defects, but at a certain temperature, their primary mode of conductance is polaron hopping. The Verwey's hypothesis explains that ferrites conduct electricity because electrons hop from one ion of the identical element to another that is randomly distributed across several crystalline lattice sites and has a different valence electron configuration. Ferrite and polyaniline samples were used to synthesize the nanocomposites using the sol-gel/in-situ technique.X-ray diffraction analysis revealed that the spinel crystals had a crystallite size of 19-61 nm.An increase from 25 emu/g to 52 emu/g in saturation Ms and an increase from 19 to 219 Oe in coercivity were observed, when the amount of spinel increases in the nanocomposite.The dielectric characteristics were frequency-dependent at lower frequencies, but frequency-invariant at higher frequencies.