Effects of ZnO-doping on structural and magnetic properties of CdFe2O4

The solid–solid interaction between Fe 2 O 3 and CdO-yielding CdFe 2 O 4 has been monitored using an XRD and a vibrating sample magnetometer. The effect of sintering temperature and dopant concentration on the bulk density of CdO/Fe 2 O 3 was investigated using the usual ceramic method. The results showed that the solid–solid interaction between the CdO and Fe 2 O 3 took place at a temperature ⩾ 600 °C yielding CdFe 2 O 4 of moderate degree of crystallinity. This reaction was much stimulated in presence of ZnO and also by increasing the calcination temperature within 700–900 °C. On the basis of magnetic measurements the possibility of formation of CdFe 2 O 4 was evidenced at a lower temperature (500 °C). These measurements also showed the stimulation effect of ZnO towards ferrite formation. The activation energy of the formation of CdFe 2 O 4 was calculated from XRD measurements and found to be 102, 75, 66, 60 and 53 kJ mol −1 for pure samples and those doped with 0.75, 1.5, 3 and 6 mol/% ZnO, respectively. The addition of ZnO (0–1.5 mol%) increased the bulk density of the investigated system which suffered a significant decrease upon increasing the dopant concentration above 1.5 mol% ZnO due to the formation of cadmium ferrite even for solids calcined at 500 °C.