XRD AND HREM STUDIES OF STRUCTURAL PHASES IN NONSTOICHIOMETRIC COMPLEX IRON-OXIDES

The influence of prolonged ball milling on structural changes of hexag onal and spinel type complex iron oxides has been studied by x-ray dif fraction and high resolution electron microscopy. The XRD and HREM res ults for ball milled SrFe12O19 ferrite show fast decomposition and for mation of Fe2O3 and SrO simple oxides. Microstructural developments fo r a powder mixture of Co(OH)(2) and Fe2O3 show the formation of cubic type structure (spinel). By comparison with the XRD results, HREM anal ysis confirmed local phase separation, with magnetic Fe3O4 and CoFe2O4 nanosize (10-30 nm) particles being formed.