Tailoring structural, magnetic, and dielectric parameters of Mg-doped CoFe₂O₄ ceramics using microwave plasma treatment for high-frequency and energy storage applications

Magnesium-substituted cobalt ferrite ceramics (Co[Formula: see text]Mg x Fe 2 O 4 where [Formula: see text], 0.4, 0.6) were prepared via the sol–gel auto-combustion technique and treated with microwave plasma discharge. X-ray diffraction of prepared samples validated the adequate substitution of the smaller cation of Mg[Formula: see text] and the formation of cubic spinel structure. The estimated average crystallite size for pristine and plasma-treated samples was 58.58[Formula: see text]nm and 56.25[Formula: see text]nm, respectively. Lattice parameters and densification slightly upsurged for plasma-treated samples. The presence of characteristic bands and functional groups of ferrites was also verified by FTIR analysis. Synthesized ferrite ceramics demonstrated increasing PL intensity for plasma-treated samples with similar band gap energy. The average band gap energy remained around 2.05[Formula: see text]eV for plasma-treated samples. The surface morphology of prepared samples also changed under plasma exposure, reducing the average grain size. Magnetic characteristics at room temperature confirmed the ferromagnetic behavior of pristine and plasma-treated specimens. After plasma treatment, the sample containing 0.4% of Mg[Formula: see text] exhibited saturation magnetization of 63.49[Formula: see text]emu/g and coercivity of 1080 Oe. Plasma treatment increased the dielectric constant while reducing the electrical resistance of magnetic ceramics. Plasma-modified ferrite with 0.6% Mg substitution exhibited minimum dielectric loss, making them suitable for high-frequency and magnetic memory devices.