Synthesis and magnetic properties of Co1−xZnxFe2O4 (x=0÷1) nanopowders by thermal decomposition of Co(II), Zn(II) and Fe(III) carboxylates

• We synthesized Co1−xZnxFe2O4 nanoparticles by decomposition of metal-carboxylates.
• Decomposition leads to a homogeneous mixture of high reactive amorphous metal oxides.
• This new method involves a faster synthesis procedure and yields virtually 100%.
• Magnetic properties of Co1−xZnxFe2O4 depend on Zn content and annealing temperature.

Nanoparticles of cobalt–zinc ferrite Co1−xZnxFe2O4 with x varying from 0 to 1.0 were prepared by a new method, the thermal decomposition of carboxylates of Fe(III), Co(II) and Zn(II). The obtained carboxylate precursor was characterized by thermal analysis and FT-IR spectroscopy. The precursor was annealed at 350, 600 and 1000 °C. It was found that the spinel cobalt–zinc ferrite was formed starting at 350 °C, but in mixture with simple oxides γ-Fe2O3, Co3O4 and ZnO. At 1000 °C Co1−xZnxFe2O4 was formed quantitatively as a single, well-crystallized phase. The saturation magnetization of the samples annealed at 1000 °C decreased significantly with increasing Zn2+ content from 83.93 emu/g (x=0) to 4.92 emu/g (x=1.0). At 350 and 600 °C the saturation magnetization had the same trend, even if there were contributions of other magnetic phases. Obtaining of spinel ferrite was evidenced by X-ray diffractometry and FT-IR spectrometry. Powder morphology was determined by scanning electron microscopy. Magnetic properties of the synthesized ferrites were investigated employing a conventional induction method.

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