Structural, Electrical, and Colossal Thermoelectric Properties of Dy_1−xSr _xMnO₃ Manganites

In the present communication, a systematic study of electrical, structural, and thermal measurements is done for low bandwidth compounds of Dy_1−xSr_xMnO₃. All the samples are prepared using solid-state reaction method. XRD patterns were refined using Rietveld method, and it is seen that all the compounds are single phased. It is demonstrated that the small polaron hopping (SPH) model valid for high-temperature regime, whereas in the low-temperature regime, the variable-range hopping (VRH) model is valid. Thermoelectric power measurements demonstrate that these samples show colossal values of thermoelectric power (S). We are perhaps reporting for the first time the largest value of S ever observed in any manganite.