Effect of substituting manganese by few cobalt content in the transport properties of Pr/Ca based manganite

A solid-state reaction technique was employed to elaborate Pr 0.7 Ca 0.3 Mn 0.98 Co 0.02 O 3 (Co-PCMO) ceramic. Electrical investigations have been conducted to comprehend the dynamic of charge carriers in the elaborated material. The DC-resistance study confirms the semiconductor behavior of the Co-PCMO system. This is attributed to the hopping mechanism in different temperature ranges. AC-conductance responses are explained according to the contribution of numerous conduction processes. It is found that the transport properties are dominated by the correlated-barrier-hopping (CBH) and the non-overlapping small polaron tunneling (NSPT) models. Then, the frequency dependence of the AC- conductance is described using the double Jonscher power law, the single Jonscher power law, and the Drude model in the low, intermediate, and high-temperature regions respectively. The application of the scaling approach confirms the validity of the time–temperature superposition principle (TTSP) in the temperature range [140K-160K]. The deviation from the Summerfield scaling model at high frequencies can be due to the change in the conduction process. Impedance responses display the important role of grain boundaries in electrical conduction. Then, it affirms the thermally activation of the relaxation phenomenon. In addition, the blocking factor's temperature dependence confirms the blocking effect's presence. This can be due to the formation of blocked zones, where some charge carriers are trapped and do not participate in the electrical conduction.