Unveiling the Effect of Zn2+ Substitution in Enrichment of Structural, Magnetic, and Dielectric Properties of Cobalt Ferrite

This work reports the detailed structural characterization of Zn2+ ion-substituted cobalt ferrite nanoparticles (CFO NPs; Co1−xZnxFe2O4; x = 0.00, 0.25, 0.50, and 0.75), prepared using a facile sol–gel method. It correlates structural changes with magnetic and dielectric properties. The as-synthesized samples were investigated by X-ray diffraction (XRD) analysis, BET surface area analyzer, energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Mössbauer spectroscopy, and impedance analyzer. The pristine sample (CFO) comprised of NPs with 25 nm size, which decreased up to 11 nm upon the formation of Zn0.75Co0.25Fe2O4. The N2 adsorption–desorption isotherm of the prepared Zn0.5Co0.5Fe2O4 sample confirmed the presence of a mesoporous structure. SEM images revealed that all prepared samples exhibited porous surface with honeycomb-like structures. The cationic distribution was described by Mössbauer spectra. The increment of Zn ions in the prepared samples resulted in sharp reduction of saturation magnetization and remanence values. The normal dielectric dispersion behavior was recorded and can be ascribed to the Maxwell–Wagner type polarization. Besides, the dielectric parameters varied by increasing Zn content in CFO NPs. This may be ascribed to O2 vacancies and Fe3+ ions in A- and B-sites. Dielectric studies revealed that, content of Zn ions beyond x = 0.25 was sufficient to reduce both dielectric constant and loss at low frequencies. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.