Effect of Nd3+ and Cd2+ ions co-substitution on the dielectric and electron transport properties of spinel strontium nanoferrites

The work reports microemulsion synthesis of spinel nanoferrites having a nominal composition of Sr1−xNdxFe2−yCdyO4 (0.0≤x≤0.1, 0.0≤y≤1.0). X-ray diffraction (XRD) patterns of powdered products annealed at 1073 K for three hours revealed the cubic Spinel structure with an average crystallite size in the range of 23–35 nm. The room temperature dc resistivity (ρ) has its maximum value for the composition Sr0.92Nd0.08Fe1.2Cd0.8O4. However, for this composition the dielectric parameters and ac conductivity have their minimum values. The magnitudes of these parameters decrease with increasing frequency at low frequency region and then show almost independent frequency behavior at higher frequencies. The results are interpreted in terms of dielectric polarization with great detail. Electrochemical impedance spectroscopy results revealed that conduction process is predominantly governed by grain boundary volume. High resistivity and low dielectric constant of investigated material suggests that it may be employed in microwave devices.