Influence of sintering temperature on the electrical and thermal properties of bulk samples of Pr2/3Sr1/3MnO3-δ

We present temperature-dependent studies on electrical and thermal properties of bulk samples of Pr2/3Sr1/3MnO3-δ synthesized at different sintering temperatures (TS). It is established that these properties intensely influenced by the sintering temperatures. Analysis of electrical resistivity data ρ(T) by means of standard models, demonstrated that electron-electron scattering processes play a key role in the conduction process in the low-temperature region. At high temperatures, the ρ(T) follows the small polaron hopping (SPH) model. Analyses of the Seebeck coefficient data S(T) in the low temperature regime illustrates that electron-magnon scattering governs the thermoelectric transport, on contrary, the high-temperature S(T) follows the SPH model. The low-temperature phonon peak in thermal conductivity κ(T) increases with increasing TS, demonstrating that a better crystallinity of Pr2/3Sr1/3MnO3 samples was obtained at higher sintering temperatures. Magnetic transitions are observed to increase with a higher TS, and the entropy change associated with the transition also increases with TS.