Template synthesis of magnetic one-dimensional nanostructured spinel MFe2O4 (M = Ni, Mg, Co)

The iron nitrate and suitable salt of nickel, cobalt, or magnesium with molar ratio of 2:1 were introduced into the pores of mesoporous silica SBA-15 via two-solvent method. The thermal decomposition of the precursors and the formation of one-dimensional nanostructured spinel ferrite in SBA-15 pores were monitored by XRD, TG–DTA, N2 adsorption–desorption, and TEM. The pure spinel MFe2O4 nanowires obtained through complete removal of the silica template with aqueous NaOH solution were confirmed by TEM and HRTEM. The spinel MFe2O4 nanowires showed increasing normal configuration and exhibited superparamagnetism in comparison with the bulk ones.