Interpretation of temperature-dependent thermoelectric power behaviour of La0.67Ba0.33MnO3 manganites

Abstract

The temperature dependence of the thermoelectric power S(T) in polycrystalline La0.67Ba0.33MnO3 has been investigated. In the ferromagnetic regime, the phonon thermoelectric power is evaluated by incorporating the scattering of phonons with impurities, grain boundaries, charge carriers and phonon. The Mott expression is used to compute the electron diffusive thermoelectric power (Scdiff.) using Fermi energy as electron-free parameter. The Scdiff infers linear temperature dependence and Sphdrag increases exponentially with temperature, which is an artefact of various operating scattering mechanisms. The behaviour of the S(T) is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between carrier diffusion and phonon drag contributions in the La0.67Ba0.33MnO3. Numerical analysis of thermoelectric power of the present model shows similar results as those revealed from experiments.