Nanocomposites of (Mg0.9Ni0.1O)x/(CoFe2O4)1-x, with 0 \(\le\) x \(\le\) 1 in weight fractions, were synthesized through the co-precipitation method followed by high-speed ball milling. The investigation of the structural, optical, and magnetic properties was conducted for the synthesized samples. X-ray diffraction (XRD) analysis confirmed the formation of CoFe2O4 and Mg0.9Ni0.1O distinct phases in the nanocomposites without any detectable impurities or minor phases. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) revealed the presence of spherical particles in both the individual phases and their nanocomposites. Raman spectroscopy exhibited strong, well-defined modes for CoFe2O4, indicating its spinel phase formation, while Mg0.9Ni0.1O displayed two broad peaks (G and D bands). X-ray photoelectron spectroscopy (XPS) was utilized to analyze the elemental compositions and oxidation states (Co2+, Fe2+, Fe3+, Mg2+, Ni2+, and O2−). The magnetic measurements revealed the soft ferromagnetic behavior of pure cobalt ferrite and a combination of weak ferromagnetism and paramagnetic behavior at high magnetic fields for pure Mg0.9Ni0.1O.
