Low-Temperature Combustion Synthesis and Properties of CoFe2O4 and CoGaxFe2 – xO4 (x = 0.05, 0.10) Nanoparticles

Resumo

CoFe₂O₄ and CoGa_xFe_{2 – x}O₄ (x = 0.05, 0.10) nanopowders have been synthesized via low-temperature combustion using cobalt, gallium, and iron complexes of malonic acid dihydrazide as precursors. Presynthesized precursors have been shown to decompose at temperatures as low as 250–300°C to form mineral residues with an amorphous structure after the combustion of the organic component. Heat treatment above 700°C leads to an onset of crystallization. The formation of the spinel structure reaches completion at 1200°C. The average particle size of the CoFe₂O₄, CoGa_0.05Fe_1.95O₄, and CoGa_0.1Fe_1.9O₄ powders has been determined to be 476, 435, and 317 nm, respectively. The electrical resistance and dielectric permittivity of the samples have been measured as functions of annealing temperature.