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

摘要

Cobalt ferrite (CoFe_2O_4) 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 NO_3~(-1) ions as oxidant. The grains observed in as-burnt powder were proved to be CoFe_2O_4 nanocrystallites with high dispersibility and low agglomeration. Both the saturation magnetization (M_s) and the remnant magnetization (M_r) were found to be highly depending upon the annealing temperature. The highest coercivity (1373 Oe) was achieved by the sample annealed at 400 ℃. Our results indicate that this method might provide a promising option for synthesizing high-quality CoFe_2O_4 nanopowder.