Electrical and thermal transport properties of Sm doped La_0·9−xSm_xTe_0·1MnO₃ (0⩽x⩽0·15) manganites

Abstract

The effect of Sm doping at the La site on the electrical and thermal transport properties of electron doped manganites La_0·9−xSm_xTe_0·1MnO₃ (0⩽x⩽0·15) has been investigated. For all samples, there exist two metal–insulator transitions in the temperature dependence of the resistivity curves ρ(T). For all samples, 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 small polaronic conduction model for all samples studied. As regards the thermal conductivity κ(T), the small thermal conduction data suggest that there exists a large Jahn–Teller distortion in the studied samples. The low temperature κ peak is suppressed by Sm doping, and κ decreases with increasing Sm doping level, which is attributed to the Sm doping hindering the mean free path of phonon increase.

Keywords:

• Electron doped
• Electrical and thermoelectric properties

This work was supported by the Higher Educational Natural Science Foundation of Anhui Province (grant no. KJ2007B130) and Anhui University Young Scientific Research Fund no. 2009QN006A and Anhui University ‘211 Project’ Teaching Quality third funding no. 39030039 and ‘211 Project’ of Anhui University.