Magnetic and thermal analysis of MFe2O4 (M = Co, Mn, Zn) nanoparticles

Magnetic nanoparticles were prepared by a wet chemical method. Precursors of MFe2O4 (M = Co, Mn, Zn) were prepared from a mixture of metal chloride and metasilicate nonahydrate aqueous solutions. The precipitates obtained in the wet chemical method were calcined to obtain MFe2O4 nanoparticles encapsulated by amorphous SiO2. The blocking temperatures T (B)'s were between 20 and 320 K, in this temperature range, the anisotropy energy of the particles decreased below their thermal energy. T (B) increased with the particle size. In order to clarify the nanoparticle formation process, differential thermal analysis and thermogravimetric (TG-DTA) measurements were performed for the as-prepared samples.