Influence of cobalt ferrite content on the structure and magnetic properties of (CoFe 2 O 4 ) X (SiO 2 -PVA) 100-X nanocomposites

Abstract (CoFe 2 O 4 ) X (SiO 2 -PVA) 100-X (X = 5, 25, 50, 75 and 95%) nanocomposites were prepared via sol-gel route and annealed at 700 and 1100 °C. The influence of CoFe 2 O 4 content on the structure, morphology and magnetic properties of nanocomposites was studied. X-ray diffraction patterns, Mossbauer and Fourier transform infrared spectra revealed the formation of CoFe 2 O 4 as unique magnetic phase. The crystallinity degree increases with the CoFe 2 O 4 content and the annealing temperature. Transmission electron microscopy images revealed the spherical shape of the obtained nanocomposites. Mossbauer spectra exhibit typical magnetic sextets, allowing the calculation of the cations distribution among tetrahedral and octahedral sites and the stoichiometry of CoFe 2 O 4 . A strong correlation between the particle morphology and the magnetic properties of nanocomposites was found. The highest saturation magnetization was identified for (CoFe 2 O 4 ) 95 (SiO 2 -PVA) 5 nanocomposite.