Effect of surfactant amount on the morphology and magnetic properties of monodisperse ZnFe2O4 nanoparticles

Abstract

The spinel ZnFe2O4 ferrites with sodium citrate as a surfactant were fabricated by polyol process. The effect of surfactant amount on the structure, morphology and magnetic properties of ZnFe2O4 ferrites were investigated by X-ray diffraction(XRD), transmission electron microscope (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and vibrating sample magnetometry (VSM), respectively. The results indicate that the structure of ZnFe2O4 ferrites is a pure cubic spinel structure with a particle size of 5–8nm. The dispersion of the synthesized ZnFe2O4 is enhanced when the mole ratio of Fe(acac)3 to sodium citrate decreases. The synthesized particles present ferrimagnetic behavior with a small hysteresis at room temperature. The increase of surfactant amount conversely leads to the decrease in the saturation magnetization value (Ms) especially when the mole ratio of Fe(acac)3 to sodium citrate decreases to 8:3. Its Ms value is drastically reduced to 18.97emu/g.