Structural, optical, and magnetic properties of sol-gel method synthesized Zn0.5NixCo0.5-xFe2O4 nanoferrites

Structural, optical, and magnetic characteristics of ferrite compounds with formula of Zn_0.5Ni_xCo_0.5-xFe₂O₄ (where x varies from 0.0 to 0.4) were prepared with the sol-gel synthesis method. Analysis using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy indicated cubic spinel structure. Notably, the crystallite size showed to be decreased from 60.25 nm to 15.85 nm as Ni content increased, accompanied by enhancements of both volume and density. Optical assessments using UV–visible spectroscopy demonstrated reduction in absorbance values from 1.01 a.u. to 0.32 a.u. A slight increase observed in the energy band gap from 5.664 to 5.684 eV with increasing Ni substitution. The magnetic properties were influenced by the replacement of Ni⁺² with Co⁺² exhibiting superparamagnetic behavior, with coercivity values ranging from 26.422 to 126.680 Oe and saturation magnetization peaking at x = 0.2 (33.239 emu/g). The magnetic behavior suggests that the Ni-doped nanoparticles are promising materials for applications in sensing, soft magnets, and hyperthermia treatments.