Eco-environmental synthesis and characterization of nanophase powders of Co, Mg, Mn and Ni ferrites

Nanocrystalline spinel ferrite MFe2O4 (M=Co, Mg, Mn, Ni) powders were synthesized by a modified coprecipitation method using iron (III) chloride, metal (II) chloride and canola oil solution as capping and dispersant agent. The canola oil is non-toxic organic vegetable oils. Thermal behavior of the as synthesized MFe2O4 nanoparticles shows three different stages of mass loss and decomposition process. FTIR measurements reveal the presence of functional groups belonging to the surfactant on the surface of the nanoparticles that can will further functionalization. The powder X-ray diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities and the crystallite size range in the order of nanometric domains. The nanoparticles structure and morphology as revealed by SEM and TEM analyses show that the all as-prepared and annealed samples contain nanoparticles with the average grain size lying between 5 and 12 nm having spherical shape. Room temperature magnetization results confirmed that the samples contain important fraction of superparamagnetic particles which reduce the values of the maximum magnetization at 20 kOe compared with the magnetization of bulk ferrites. In the case of cobalt ferrite nanoparticles were observed high values of magnetization and coercive field as result of greater average particles size. The study confirmed that canola oil can be used in synthesizing CoFe2O4, MgFe2O4, MnFe2O4 and NiFe2O4 nanoparticles with diameters lying in the domain of 10 nm.