Electrical and thermal transport properties of the Pr-doped La0.9−xPrxTe0.1MnO3  (0≤x≤0.9) manganites

The effect of Pr doping at the La site on electrical and thermal transport properties of the electron-doped manganites La0.9−xPrxTe0.1MnO3 (0≤x≤0.9) has been investigated. For the samples with x≤0.36, there is a insulator-metal (I-M) transition while the samples with x≥0.54 display semiconducting behavior over the whole measured temperature range. For x≤0.36, the thermopower S changes sign from negative to positive with decreasing temperature and the crossover temperature increases with increasing Pr doping content x. For the samples with x≥0.54, S shows a positive sign over the whole temperature range studied. Both ρ(T) and S(T) data in the high temperature range can be well described by the variable-range-hopping (VRH) model for all samples studied. In the low temperature region, the ρ(T) and S(T) data for the sample with x≤0.36 are analyzed on the basis of the electron-magnon scattering mechanism. As regards the thermal conductivity k(T), the low temperature k peak is suppressed by Pr doping and k decreases with increasing Pr doping level. The result is analyzed as regards the combined effect of the disorder and antiferromagnetic (AFM) interaction induced by Pr doping.