Role of Ag Doping on Structural, Electrical, and Dielectric Properties of MgFe 2 O 4 Synthesized via the Sol–Gel Route

Here, we studied the impact of silver doping in the physical properties of magnesium-ferrite (MgFe 2 O 4 ) synthesized via the sol–gel (Pechini) route. XRD refinement indicates that the undoped sample crystallizes in a cubic structure with space group F d-3 m. However, the doped samples possess metallic silver with the cubic spinel phase. Electrical measurements were carried out by complex impedance spectroscopy at room temperature in the frequency range (100 Hz to 10 6 Hz). The electrical conductance decreases with increasing of silver content. By fitting the experimental data using Jonscher’s universal power law, it is found that the hopping occurs between neighboring sites. The Nyquist plot shows semicircular arcs, and an equivalent electrical circuit was proposed to explain the impedance results for each sample. The investigation of the normalization curves impedance and electrical modulus normalization curves showed a shift in the two peaks, confirming the presence of short-range charge carrier motion. The dielectric constant and dielectric loss decrease with increasing frequency. This behavior can be explained by a Maxwell–Wagner-type polarization.