Studies of electrical and thermal transport properties of the electron-doped manganite Sr 0.9Ce 0.1MnO 3

Abstract

Systematic studies of X-ray, resistivity ( ρ ), Hall effect, thermal conductivity ( κ ), and thermopower ( S ) have been performed on polycrystalline Sr 0.9Ce 0.1MnO 3 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 ( R H ) and thermopower ( S ) show negative values, indicating that the carriers in the sample are electrons. In the whole measuring temperature range, d κ / d T > 0 , with rather low thermal conductivity value, is related to unusually large static and dynamic lattice distortions of the MnO 6 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.