Studies of electrical and thermal transport properties of the electron-doped manganite Sr0.9Ce0.1MnO3

Systematic studies of X-ray, resistivity (ρ), Hall effect, thermal conductivity (κ), and thermopower (S) have been performed on polycrystalline Sr0.9Ce0.1MnO3 sample. While cooling, it undergoes a first-order metal-insulator transition at around 318 K, which is associated with a structural transition due to Jahn-Teller ordering. Both Hall coefficient (RH) and thermopower (S) show negative values, indicating that the carriers in the sample are electrons. In the whole measuring temperature range, dκ/dT>0, with rather low thermal conductivity value, is related to unusually large static and dynamic lattice distortions of the MnO6 octahedra. Below 200 K, both ρ and S follow the variable range hopping (VRH) model. In contrast, in the temperature range of 200-320 K, a small polaron behavior can be invoked by the electron-phonon interaction.