Magnetic and microwave absorption properties of FeCo/CoFe2O4 composite powders

FeCo/CoFe2O4 composite powders were synthesized by conducting solution combustion method in a closed system and using microwave heating. Phase evolution studies by X-ray diffraction method showed the appearance of FeCo phase at the cobalt to ferric molar ratio of 2, while the impure CoO phase was formed at the higher molar ratio. The synthesized powders had spongy structure with spherical nanoparticles (∼30 nm), as observed by scanning and transmission electron microscopes. The highest saturation magnetization of 99 emu/g and lowest coercivity of 450 Oe was attained by the CoFe2O4/17 wt % FeCo composite powders. The paraffin-FeCo/CoFe2O4 composite sample exhibited a reflection loss intensity value of −20 dB in C band (4–8 GHz) which showed that the metal/ferrite composite powders may be a promising candidate for microwave absorption applications.