Could Mg content control the conduction mechanism of Ba Co Zn-W-type hexagonal ferrites?

Electrical properties as a function of composition, frequency and temperature for a series of W-type hexagonal ferrites with the general formula BaCoZn1−xMgxFe16O27; 0≤x≤0.6 prepared using the conventional ceramic method were studied. These samples are semiconductor-like materials, where the ac conductivity increases with increasing temperature. The results show that the conduction mechanism depends on the Mg2+ substitution. The transition temperature (Tσ) increases with increasing Mg content and gives a hump at x=0.5; after that Tσ decreases again. Both the ac conductivity and dielectric constant vary with Mg content and reach the highest value at x=0.5, due to the highest value of the ratio of Fe2+/Fe3+ at x=0.5. The peak value of the dielectric constant depends on the Mg content x.