The temperature dependence of the electrical resistivity q, thermoelectric power S and the magnetic
susceptibility v of La0.7–xBixSr0.3MnO3 (x ¼ 0.05, 0.10, and 0.15 at. %) manganites were
investigated. La0.7–xBixSr0.3MnO3 crystallizes in a single phase rhombohedral structure with parasitic
phase inclusions. With increasing Bi concentration, a systematic decrease in the ferromagnetic
transition temperature (Tc), the metal-semiconducting transition temperature (Tms1) and also the
values of activation energies Eq and ES from q(T) and S(T) were observed. On the other hand, in
the high-temperature (T > Tms) paramagnetic semiconductor regime, the adiabatic small polaron
hopping model fit well, thereby indicating that polaron hopping might be responsible for the conduction
mechanism. In addition, the thermoelectric power data at low temperatures were analyzed
by considering both the magnon and the phonon drag concept, while the high-temperature data
were confirmed a small polaron hopping conduction mechanism.