The magnetization of substituted ferrite nanoparticles synthesized by co-precipitation method
depends mostly on parameters such as reaction temperature, pH of the suspension, initial molar
concentration, etc. [12]. Ultra fine particles of Fe3O4 are prepared by co-precipitating aqueous
solutions of (NH4)2Fe(SO4)2 and FeCl3 mixtures, respectively, in alkaline medium. (NH4)2Fe(SO4)2
and FeCl3 solutions are mixed in their respective stoichiometry (i.e, ratio Fe +2: Fe +3 = 1:2). The
mixture is kept at 80 oC. This mixture is added to the boiling solution of NaOH (0.5 mol. is dissolved
in 600 ml of distilled water) within 10 second under constant stirring. Magnetite is formed by
conversion of metal salts into hydroxides, which take place immediately, and transformation of
hydroxides into ferrites. The solution is maintained at 100 oC for 1.5 h.