| Summary: | (Co<sub>0.4</sub>Zn<sub>0.4</sub>Ni<sub>0.2</sub>Fe<sub>2</sub>O<sub>4</sub>)<sub>α</sub>(SiO<sub>2</sub>)<sub>(100−α)</sub> samples obtained by embedding Co<sub>0.4</sub>Zn<sub>0.4</sub>Ni<sub>0.2</sub>Fe<sub>2</sub>O<sub>4</sub> nanoparticles in SiO<sub>2</sub> in various proportions were synthesized by sol-gel process and characterized using thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, and magnetic measurements. Poorly crystalline Co–Zn–Ni ferrite at low annealing temperatures (500 °C) and highly crystalline Co–Zn–Ni ferrite together with traces of crystalline Fe<sub>2</sub>SiO<sub>4</sub> (800 °C) and SiO<sub>2</sub> (tridymite and cristobalite) (1200 °C) were obtained. At 1200 °C, large spherical particles with size increasing with the ferrite content (36–120 nm) were obtained. Specific surface area increased with the SiO<sub>2</sub> content and decreased with the annealing temperature above 500 °C. Magnetic properties were enhanced with the increase in ferrite content and annealing temperature.
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