Abstract
Magnesium–zinc ferrite (Mg0·6Zn0·4Fe2O4) powder was prepared through the ceramic route by the calcination of a stoichiometric mixture of magnesium, zinc and iron oxides. The ferrite powders (Mg0·6Zn0·4Fe2O4) were then sintered at 1300°C for 4 h. Both the ferrite powders and sintered pellets were subjected to isothermal reduction in pure hydrogen at 500–700°C. Based on thermogravimetric analyses, the reduction behaviour of magnesium–zinc ferrite was systematically studied. The initial ferrite powder, the sintered bodies and the various reduction products were characterised by X-ray diffraction analyses, scanning electron microscopy and vibrating sample magnetometer to reveal the effect of sintering and hydrogen reduction on composition, microstructure and magnetic properties of Mg0·6Zn0·4Fe2O4. It is found that the sintered pellets had enhanced magnetic properties, whereas the saturation magnetisation increased and the coercivity decreased sharply. Homogenous Fe/ZnO/MgO nanocrystalline composite of ∼62·1 nm in size was obtained after the reduction of initial Mg0·6Zn0·4Fe2O4 powder. The magnetic properties of these Fe/MgO/ZnO composites were found to be improved according to the reduction temperature, whereas the saturation magnetisation increased from to 34·18 to 109·7 emu g−1 and the coercivity values decreased from 157·7 to 136·4 Oe.