Impact of calcination temperature on electrical and dielectric properties of SrGa0.02Fe11.98O19-Zn0.5Ni0.5Fe2O4 hard/soft nanocomposites

In this study, a series of SrGa0.02Fe11.98O19-Zn0.5Ni0.5Fe2O4 hard/soft nanocomposites (SrGaFeO-ZnNiFeO H/S NCs) were synthesized via a single-pot (citrate sol–gel) approach by applying different calcination temperatures. The electrical and dielectric properties of the SrGaFeO-ZnNiFeO H/S NCs based on the calcination temperatures in between 800 and 1100 °C were systematically investigated with an impedance analyzer of up to 3.0 MHz frequency and within 20 and 120 °C temperature range. Both electrical and dielectric parameters, such as ac/dc conductivity, dielectric loss, dielectric constant, and tangent loss, were measured for a given calcination temperature. It has been found that AC conductivity generally conforms the power law rules, largely dependent on calcination temperatures. Impedance analysis has observed that the conduction mechanisms of SrGaFeO-ZnNiFeO H/S NCs at various calcination temperatures are mainly attributable to grain–grain boundaries. The dielectric constant of SrGaFeO-ZnNiFeO H/S NCs shows normal dielectric distribution with frequency, largely dependent on calcination temperatures. Ultimately, the observed change in dielectric properties with frequency can be attributed to the conduction mechanism in most compound ferrites, which can be phenomenologically explained by Koop’s model.