Enhanced Magnetic Softness and Specific Capacitance in Mg0.5Zn0.5Fe2O4 Nanoferrites

In this study, magnesium-zinc ferrite Mg _0.5 Zn _0.5 Fe ₂ O ₄ nanoparticles were successfully synthesized via a PVP-assisted co-precipitation method, followed by thermal annealing at temperatures ranging from 600°C to 1000°C. The influence of annealing temperature on the structural, morphological, magnetic, and electrochemical properties was systematically investigated. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase cubic spinel structure, with crystallite size increasing (13nm to 20nm) as a function of thermal treatment. Fourier Transform Infrared (FTIR) spectroscopy corroborated the structural integrity of the ferrite phase, revealing characteristic metal-oxygen absorption bands at approximately 553–567 cm⁻¹ (tetrahedral sites) and 451–466 cm⁻¹ (octahedral sites), while spectral shifts indicated a thermal-induced redistribution of cations within the lattice. Morphological analysis via Dynamic Light Scattering (DLS) demonstrated a corresponding increase in hydrodynamic diameter and polydispersity at elevated temperatures. Magnetic measurements using a Vibrating Sample Magnetometer (VSM) revealed a transition from ferromagnetic to soft magnetic behavior, characterized by a significant reduction in coercivity (Hc) to 45.88 Oe and an optimization of saturation magnetization (Ms) at 900°C. Furthermore, electrochemical analysis via Cyclic Voltammetry (CV) indicated that the enhanced crystallinity achieved at higher annealing temperatures significantly improves specific capacitance, reaching a maximum of 7.68 F/g. These findings suggest that thermally tuned Mg _0.5 Zn _0.5 Fe ₂ O ₄ nanoparticles possess dual-functionality, making them promising candidates for high-frequency magnetic devices and pseudocapacitive energy storage systems.