Effect of Li2O doping on electrical properties of CoFe2O4

The solid-solid interactions between cobalt and ferric oxides to produce Co Fe2O4 were followed up using XRD investigation. The effect of Li2O-doping o n the ferrite formation was also studied. The electrical and dielectric par ameters of pure and doped mixed solids precalcined at 1273 K were measured using d.c and a.c instruments. The dopant concentration was varied between 0.5 and 6 mol% Li2O. The results obtained revealed that Li2O doping much en hanced the ferrite formation due to an increase in the mobility of the reac ting species. The addition of the smallest amount of Li2O (0.5 mol%) resulted in measurab le variations in the electrical constants (rho, E-a, epsilon', epsilon " an d tan delta). Resistivity increased upon increasing the dopant concentratio n up to 1.5 mol% exceeding the values measured for the undoped sample. Furt hermore, the presence of 6 mol% Li2O brought about a significant decrease o f electrical resistivity. Also, the activation energy decreased with increa sing the dopant concentration. The dielectric constant behaves according to epsilon = const. 1/rho(1/2) The Li2O-doping modified the values of different dielectric constants, the change in these constants was found to be strongly dependent on the amount of Li2O added. These results have been discussed in terms of the potentiali ty of Li2O in increasing the mobility of the reacting species involved in t he ferrite formation. (C) 1999 Elsevier Science BN. All rights reserved.