Study of electrical properties of (Pr/Ca/Pb)MnO₃ ceramic

Characterization of the electrical properties of Pr_0.65Ca_0.25Pb_0.1MnO₃ ceramic, prepared by the solid-state method, is conducted using the impedance spectroscopy technique. Ac-conductivity measurements reveal the presence of two electrical behaviors. A semiconductor character obtained at low-temperature ranges of 80–160 K, and a metallic behavior found at high-temperature ranges of 180–400 K. The temperature dependence of the exponent s confirms the contribution of two conduction processes in the transport mechanism. In the range of T < 140 K, the non-overlapping small polaron tunneling (NSPT) is the predominant mechanism. However, for T > 140 K, the conduction process is governed by the correlated barrier hopping (CBH) model. Finally, beyond T = 250 K, the dc-conductivity is characterized by the appearance of a saturation region.