Thermal and thermoelectric properties of potassium-doped Pr_0.6Sr_0.4-xKxMnO₃ (x=0.05 and x=0.1)

The temperature dependence of thermal conductivity and thermopower was studied for a series of monovalent doped Pr0.6Sr0.4-xKxMnO3 (with x = 0.05 and x = 0.1). The influence of the external magnetic field up to 2 T was investigated with a focus on the vicinity of the ferromagnetic-paramagnetic transition. The analysis of kappa(T) data suggests that thermal transport is governed by phonon scattering processes, as both the electronic and magnon contribution to total thermal conductivity is well below 1%. The temperature behavior corresponds to typical curves observed in other manganites, both in shape and value. Thermopower investigation S(T) showed a negative value in all studied temperatures, and for further analysis was divided into ferromagnetic and paramagnetic regions. In the first one, the experimental data followed a standard empirical equation S0+S3/2T3/ 2+S4T4, bringing information about the prevailing electron-magnon scattering processes. For the latter one, the polaron hopping model was used.