Synthesis, structural characterization, and frequency dependent dielectric analysis of cobalt-doped magnesium ferrite nanoparticles for advanced energy storage systems

Pure and cobalt-doped magnesium ferrite (Mg_1-xCo_xFe₂O₄, x  = 0, 0.03, 0.06, and 0.09) nanoparticles were successfully synthesized via solgel method. X-ray diffraction (XRD) analysis conducted at room temperature validated the formation of single-phase spinel ferrites and assessed the material’s purity and crystal structure. Fourier transform infrared spectroscopy (FTIR) explored the diverse vibrational modes and the bonding arrangments between the atoms. Scanning electron microscopy (SEM) offered valuable insights into nanoparticles'morphology, shape, and size. Energy dispersive X-ray (EDX) spectroscopy was employed to analyze the composition of the prepared nanoparticles. An LCR meter was used at room temperture to analyze the dielectric properties of the synthesized nanoparticles. The study focused on the frequency dependence of key parameters, including capacitance ($C_p$) and real and imaginary parts of the dielectric constant (${\epsilon }_r^{\prime }\&{\epsilon }_r^{″}$), tangent loss ($tan\delta$) and ac conductivity (${\sigma }_{\mathrm{ac}}$). The dielectric measurements notably revealed high values of dielectric constants, particularly at lower frequencies. Doping of cobalt into pure MgFe₂O₄ has demonstrated a notable improvement in both charge storage and transport properties leading to enhanced dielectric parameters. The outcomes of this study suggest the promising applications of Mg_1-xCo_xFe₂O₄ nanoparticles in a wide range of energy storage devices.