Abstract The mixed metal oxides have a significant increase in material science engineering applications. Mixed metal oxides of (1-x)NiO/xFe2O3 nanoparticles (NPs) (x = 0.0, 0.3, 0.5, 0.7 and 1) were obtained by the mechanical mixing method, and their films were achieved by the drop coating method. Raman spectroscopy was used for identifying these NPs. Dielectric relaxation and ac conductivity behavior of (1-x)NiO/xFe2O3 NPs (x = 0.0, 0.3, 0.5, 0.7 and 1) were studied. The dielectric constant, e1, and the dielectric loss, e2, for pure Fe2O3 NPs were found higher than that for pure NiO NPs. Moreover, with increasing the concentration of Fe2O3 NPs, the value of e1 and e2 increased in the mixed (1-x)NiO/xFe2O3 NPs. The complex dielectric modulus the real, M1, and imaginary, M2, parts were investigated as well as the dielectric relaxation time. The total conductivity was investigated as a function of frequency for (1-x)NiO/xFe2O3 NPs (x = 0.0, 0.3, 0.5, 0.7 and 1) then the improvement of its values was verified due to the addition of Fe2O3 NPs. The AC activation energy, ΔEac, was calculated, which increases (0.0081–0.0090) at a constant frequency of 1 MHz as Fe2O3 NPs content increased. These values of ΔEac reflected that the hopping conduction is the common current transport mechanism. On the other hand, the activation energy of the relaxation process, ΔEr, decreased (0.875–0.322) as a function of Fe2O3 NPs content increased.
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