Reduction under hydrogen of ferrite MFe2O4 (M: Fe, Co, Ni) nanoparticles obtained by hydrolysis in polyol medium: A novel route to elaborate CoFe2, Fe and Ni3Fe nanoparticles

► Spinels nano-particles MFe2O4 (M: Co, Fe or Ni) are obtained by hydrolysis in polyol medium. ► Gentle reduction under hydrogen flow of spinel nano-particles yields metal and alloy nanoparticles. ► TEM and X-ray analysis show that CoFe2, Fe and Ni3Fe nano-particles are monocrystalline particles with size less than 160 nm. ► Iron with size of 150 nm presents ferromagnetic behavior. ► CoFe2 alloy with size of 55 nm could be considered as a superparamagnetic material.