Tuning morpho-structural and magnetic characteristics of (Co0.5Zn0.5Bi0.2Fe1.8O4)x(SiO2)100-x nanocomposites via composition and calcination temperature

• The particle size increased from 30 nm to 100 nm. • Single Co 0.5 Zn 0.5 Bi 0.2 Fe 1.8 O 4 phase were obtained at all temperature. • The NCs calcined at 1200 °C displayed superparamagnetic-like behavior. • The magnetic parameters increased with the ferrite content. The influence of various proportions of Co 0.5 Zn 0.5 Bi 0.2 Fe 1.8 O 4 (x = 25–100 %) dispersed in a SiO 2 matrix, as well as the effect of calcination temperature on the morpho-structural and magnetic characteristics of (Co 0.5 Zn 0.5 Bi 0.2 Fe 1.8 O 4 ) x (SiO 2 ) 100-x nanocomposites (NCs) explored using X-ray diffraction (XRD), atomic force microscopy (AFM) and vibrating sample magnetometry (VSM). At all calcination temperatures, the NC with x = 100 % showed the well crystallized phase of ferrite, while the NCs with x = 25–75 % displayed well crystallized ferrite attended by cristobalite and quartz. The particle size increased progressively from about 30 nm at low calcination temperatures (300, 600 and 900 °C) to about 100 nm at 1200 °C, along with the ferrite content in the composition. The correlation between ferrite crystallite and nanoparticle size indicated that the SiO 2 outer glaze is rather a constant layer of about 2–4 nm. The remanent magnetization, saturation magnetization, coercivity and anisotropy constant increased with the ferrite content dispersed in the SiO 2 matrix. In this regard, dispersing mixed Co-Zn-Bi ferrite nanoparticles into the SiO 2 matrix minimized the particle agglomeration, and allowed a fine tuning of particle size and magnetic characteristics. The magnetic behavior tailored by particle size, ferrite content and calcination temperature allow mixed ferrites to meet the requirements of specific applications in multifunctional material fields such as magnetic coatings or thin films