Structural and magnetic properties of pure and doped nanocrystalline cadmium ferrite

The solid-state reaction between pure and alumina or magnesia doped Cd/Fe mixed oxides have been investigated using DSC, XRD, IR, TEM and VSM techniques. Equimolar proportions of cadmium nitrate and α-Fe2O3 were employed and also Al and Mg were added as aluminum and magnesium nitrates. Pure and doped mixed solid were subjected to thermal treatment at 500-1200 deg. C. The results obtained showed that the degree of propagation of the reaction between Fe2O3 and CdO yielding CdFe2O4 increased as a function of calcination temperature up to 1000 deg. C. However, heating of pure mixed solids at 1000 deg. C for 3 h was sufficient to effect complete conversion of the reacting solids to Cd-ferrite. The crystallite size of produced CdFe2O4 was reduced nanocrystalline range due to Al2O3 or MgO-doping. The microstructure and magnetic properties of the investigated solids were strongly dependent on the calcination temperature and doping process. The maximum saturation magnetization (7.79 emu/g) was achieved by doping with 2 mol% MgO at 1100 deg. C. The formation activation energy of CdFe2O4 was evaluated be 72, 64 and 27 kJ mol-1 for pure mixed solids and those doped with 6 mol% Al2O3 and 6 mol% MgO, respectively.