Influence of SiO 2 Embedding on the Structure, Morphology, Thermal, and Magnetic Properties of Co 0.4 Zn 0.4 Ni 0.2 Fe 2 O 4 Particles.

(Co 0.4 Zn 0.4 Ni 0.2 Fe 2 O 4 ) α (SiO 2 ) (100-α) samples obtained by embedding Co 0.4 Zn 0.4 Ni 0.2 Fe 2 O 4 nanoparticles in SiO 2 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 2 SiO 4 (800 °C) and SiO 2 (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 2 content and decreased with the annealing temperature above 500 °C. Magnetic properties were enhanced with the increase in ferrite content and annealing temperature.