Low-temperature auto-combustion synthesis and magnetic properties of cobalt ferrite nanopowder

Cobalt ferrite (CoFe2O4) nanopowder was prepared by a low-temperature, auto-combustion method. The thermal evolution of the precursor, as well as the microstructure, morphology and magnetic properties of as-synthesized powder were studied. The results revealed that the synthetic process was a thermally induced redox reaction with carboxyl group as reductant and NO3−1 ions as oxidant. The grains observed in as-burnt powder were proved to be CoFe2O4 nanocrystallites with high dispersibility and low agglomeration. Both the saturation magnetization (Ms) and the remnant magnetization (Mr) were found to be highly depending upon the annealing temperature. The highest coercivity (1373 Oe) was achieved by the sample annealed at 400 °C. Our results indicate that this method might provide a promising option for synthesizing high-quality CoFe2O4 nanopowder.