X-Ray Powder Diffraction Study on the Hydrothermally Obtained Zinc-Manganese Ferrites

The structural study by X-ray powder diffraction applied to the solid solutions formed between a normal spinel ZnFe2O4 and a partly inverse spinel MnFe2O4 substituted with Al3+ ions indicates the difference of cation arrangement, and of the oxidation degree of manganese, in the ternary and quaternary spinel oxides obtained hydrothermally, compared to that of ferrites sintered at high temperatures. The 'low-temperature' aluminium substituted Zn-Mn ferrites are cation deficient, nonstoichiometric structures, which may be considered as solid solutions formed between a stoichiometric Zn-Mn ferrite and a defect spinel, gamma-Fe2O3, Evolution of such defect systems during thermal treatment results in the formation of nearly stoichiometric spinel fel rites at 1000 degrees C.