Admittance spectroscopy investigation of Pr0.65Ca0.25Sr0.1MnO3 system

Structural and transport properties of Pr0.65Ca0.25Sr0.1MnO3 ceramic have been reported. A solid-state reaction method was used to elaborate the studied sample. X-ray diffraction analysis authenticates the orthorhombic structure of the investigated compound with Pnma space group. Using the impedance spectroscopy technique, the electrical properties were examined. Indeed, the DC conductivity investigation proves the semiconductor behavior of Pr0.65Ca0.25Sr0.1MnO3 ceramic. Then, a saturation region is observed at round ambient temperature. The measured electrical conductivity of the studied sample indicates that such system can be used as cathode for constructing solid oxide fuel cell. Impedance measurements show a major contribution of grain boundaries in the transport properties of the material. On the other hand, we elaborate an electrical equivalent circuit model to explain the relaxation phenomenon in the impedance spectra and to fit Nyquist plots. Additionally, the experimental result of the conductivity spectra was interpreted using Jonscher power law and Drude model at low and high temperatures ranges, respectively. At high frequencies, the electrical transport is explained by the contribution of the correlated barrier hopping process. Using the scaling model, the validity of the time temperature superposition principle was investigated. However, a large deviation from the Summerfield scaling is observed at high frequencies.