Improved Electrical Properties Displayed by Mg²⁺-Substituted Cobalt Ferrite Nano Particles, Prepared Via Co-precipitation Route

In this reported study, magnesium-substituted cobalt ferrite nanoparticles (Co_1−xMg_xFe₂O₄, x = 0.0, 0.20, 0.35, 0.50) have been investigated. The samples were prepared via a wet chemical co-precipitation route and were calcinated at 800 °C for 6 h. The structural, electrical, and dielectric properties of these samples were studied using XRD, SEM, FTIR, impedance analyzer, and LCR meter. The XRD diffractograms established the development of FCC spinel arrangement with decreasing crystallite size from 20 to 30 nm without any additional impurity peak confirming the purity of the samples synthesized. The FTIR spectra established the existence of tetrahedral (A) and octahedral (B) lattice sites in the structural arrangement. The SEM images showed uniform nano-spherical particle formation with minimum porosity. No extra phase or impurity was found, confirming the effectiveness of the co-precipitation route. The dielectric properties of the synthesized samples measured at ambiance temperature against frequency range of 10³ Hz to 5 MHz showed massive enhancement of dielectric constant (on the order of 10⁴ at 100 Hz) which was comparable to traditional ceramics (having a dielectric constant in the range of 10⁴–10⁶), which are often rendered suitable for capacitor applications. Furthermore, the low values of dielectric loss tangent at high frequencies verified its potential usage in microwave applications. A significant contribution of both long- and short-range order in hopping as well as an increase in grain boundary density was confirmed by complex electric modulus analysis. The DC electrical resistivity measurement against increasing temperatures was done, showing a typical decreasing trend with increasing temperature, validating the semiconductor nature of synthesized nanoparticles with varying compositions. The drift mobility was further calculated from the DC resistivity data.