Study and Evaluation of Zn_0.2Co_0.8Fe₂O₄ Nanocrystalline Spinel Ferrites for Antimicrobial and Anticancer Applications

Zinc-added cobalt ferrite with a composition of Zn_0.2Co_0.8Fe₂O₄ was synthesized using the sol-gel method with poly-(vinyl alcohol) as a chelating agent. The structural properties of the as-synthesized ferrite were determined using X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). The measured structural parameters revealed the formation of a single-phase cubic spinel structure in the sample. Various structural parameters were measured to identify the variations upon the addition of Zn²⁺. The surface of the sample was coated with SiO₂ and NH₂ to achieve better catalytic performance. The surface coating of the sample was confirmed using FTIR and energy-dispersive X-ray analysis (EDAX). The optical energy gap of the sample was calculated using a Tauc plot derived from the UV-vis spectra, and the Urbach energy of the sample was calculated. The bandgap energy and Urbach energy were determined to be 2.14 and 0.04 eV, respectively. This confirmed the semiconducting nature of the sample. Thermogravimetric analysis was performed using differential scanning calorimetry. Surface morphology and elemental analyses were performed using field-emission scanning electron microscopy (FESEM) with EDAX. The almost uniform size of the particles confirmed the effectiveness of the synthesis method. The direct-current electrical conductivity was measured using the two-probe method, and the dielectric properties were measured using an impedance analyzer in the frequency range of 100 Hz-10 MHz. The variations in the dielectric properties are also discussed in this study. The proposed cation distribution was confirmed using Mössbauer spectroscopy. Magnetic measurements were performed using a vibrating sample magnetometer, and the obtained magnetization (37.16 emu/g) and coercivity (0.209 Oe) confirmed the soft ferromagnetic nature of the Zn-added Co ferrite. The antibacterial and antifungal activities of Zn_0.2Co_0.8Fe₂O₄ against Escherichia coli and Aspergillus niger were evaluated. These findings suggest that Zn_0.2Co_0.8Fe₂O₄ nanoparticles have potential applications in biomedicine, such as in magnetic hyperthermia treatment and drug delivery systems.