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

•An one-step, facile and inexpensive synthetic route to monodisperse ZnFe2O4 nanoparticles is described.•The sodium citrate stabilized ZnFe2O4 nanoparticles with a diameter in the 5–8 nm size range can be easily dispersed in water.•The synthesis is very robust in terms of variations of experimental parameters.•ZnFe2O4 nanoparticles present ferrimagnetic behavior at room temperature with a small hysteresis.

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 5–8 nm. 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 18.97 emu/g.

Graphical abstractPolyol process to monodisperse ZnFe2O4 nanoparticles.Figure optionsDownload full-size imageDownload as PowerPoint slide