Influence of SiO2 Embedding on the Structure, Morphology, Thermal, and Magnetic Properties of Co0.4Zn0.4Ni0.2Fe2O4 Particles

Abstract

(Co_0.4Zn_0.4Ni_0.2Fe₂O₄)_α(SiO₂)_(100-α) samples obtained by embedding Co_0.4Zn_0.4Ni_0.2Fe₂O₄ nanoparticles in SiO₂ 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 Fe₂SiO₄ (800 °C) and SiO₂ (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 SiO₂ content and decreased with the annealing temperature above 500 °C. Magnetic properties were enhanced with the increase in ferrite content and annealing temperature.

Keywords: Co0.4Zn0.4Ni0.2Fe2O4; annealing temperature; crystalline phase; magnetic behavior; silica matrix.