Electrical, magnetic and thermal properties of Pr_{0.6- x}Bi_xSr_0.4MnO₃ manganites

In the present communication, we report the electrical, magnetic and thermal properties of Bi-doped Pr_0.6Sr_0.4MnO₃ (PSMO) compounds. These measurements show that the transition temperature decreases with Bi-content. Analyses on the measured electrical resistivity and thermoelectric power data indicate that the small polaron hopping model is operative in the high temperature paramagnetic phase for all samples. The thermal conductivity, κ(T) for samples studied in the present work is found to be low which is essentially due to Jahn-Teller (JL) distortion in the samples. It is observed that κ(T) is seen to decrease with increase in doping concentration of Bi which is possibly due to the formation of JT polarons which act as scattering centers. From specific heat measurements, we observe reduction in values of entropy change with increase in bismuth content which suggests that the magnetic inhomogeneity increases with Bi substitution.