Synthesis and characterization of nanosized ZnFe2O4 powders obtained by sonochemistry

Zink ferrite powders are widely studied due to their application in many fields, such as anode materials for lithium-ion batteries, gas sensors, magnetic materials, catalytic materials, and antibacterial materials in water treatment. We present the structural and magnetic properties of nanosized ZnFe2O4 powders synthesized by sonochemistry and discuss their dependence on the synthesis conditions. The XRD spectra of the as-prepared samples reveal the presence of both an amorphous and a crystalline ZnFe2O4 phase. In the spectrum of the sample annealed at 500 oC, the peaks are considerably narrower and of higher intensity, proving the sample’s higher degree of crystallinity. The room temperature Mössbauer spectra of the as-prepared and annealed ZnFe2O4 samples showed a superparamagnetic doublet spectrum. Both kinds of samples exhibited paramagnetic behavior at room temperature, which is typical of the normal spinel structure. A very narrow hysteresis curve at 4.2 K was recorded, which could be expected for superparamagnetic particles in the ferrimagnetic state at low temperatures.

Acknowledgments: The work was supported by the Bulgarian National Science Fund under contract KP-06-N48/5 "Multifunctional composite structures based on ferrites (including magneto electrics) and carbon materials" and by the Bulgarian National Science Fund under contract KP-06-India-2 “Usage of thin ZnFe2O4 films for various spintronic devices”. This work was also supported by a joint research project between the Bulgarian Academy of Sciences and WBI, Belgium, and by a joint research project between the Bulgarian Academy of Sciences and the Institute of Low Temperature and Structure Research, Polish Academy of Sciences.