Effect of changing magnetite percentage on structural and magnetic properties of cobalt ferrite prepared by the sol-gel method

Abstract

The present research properly fabricated Co_1−xFe₂O₄ nanoparticles (NPs) with a spinel structure (where x=0.3, 0.6, and 0.9, which corresponds to Co_0.4Fe₂O₄, Co_0.4Fe₂O₄, and Co_0.4Fe₂O₄) via a sol-gel approach with ferric nitrate, cobalt nitrate, and citric acid as precursors are used. The powders are compressed, sintered at 1000°C for 6 hours, then calcined at 500°C for 4 hours to produce dense pellets. X-ray diffraction revealed the production of a single-phase cubic spinel structure with a favored (311) orientation, and the crystallite size is determined to be between 40 and 80 nm. Vibrating sample magnetometry (VSM) demonstrated soft magnetic behavior with low coercivity and remanence, notably for the composition of Co_0.4Fe₂O₄ NPs. Microwave absorption characteristics determined with an X-band (8-12.5 GHz) network analyzer revealed that variations in Co content significantly affected density, porosity, and grain size, leading to changes in attenuation coefficient and scattering parameters (S11 and S21), with absorption following a Gaussian-type distribution. Furthermore, antibacterial activity as measured by the agar diffusion technique showed efficient suppression of Escherichia coli and Staphylococcus aureus, with greater activity versus the Gram-negative strain. These findings emphasize the multifunctionality of Co-doped cobalt ferrite nanomaterials.