Conventional versus microwave combustion synthesis of CoFe2O4 nanoparticles

Cobalt ferrite (CoFe2O4) nanoparticles have been synthesized by sol-gel autocombustion method ignited by conventional and microwave heating techniques. The precursor solutions were prepared with different fuel types such as citric acid and urea. The ignition technique and fuel type affected the phase evolution, microstructure, and magnetic properties of CoFe2O4 nanoparticles. X-ray diffraction results revealed that the single-phase and well-crystallized CoFe2O4 nanoparticles would only be formed using citric acid as fuel and after calcination at 600 degrees C. Microwave ignition resulted in the formation of larger sphere-like CoFe2O4 particles, possibly due to the contribution of microwave-absorbing products in attaining of higher temperatures. Furthermore, the single-phase CoFe2O4 nanoparticles synthesized by microwave ignition exhibited the higher saturation magnetization (Ms = 77 emu/g) compared to that of conventional method (Ms = 53 emu/g), due to their larger particle size and higher inversion coefficient.