Mechanisms of heat carriers scattering in La1−xSrxMnO3 single crystals near the phase transition temperature

We measured the specific heat (CP), the thermal diffusion (η) and thermal conductivity (κ) of single crystals La1−xSrxMnO3 (x = 0, 0.175, and 0.20), depending on the temperature and magnetic field. It is shown that in the behavior of κ(T) and η(T) near TС the lows are observed due to phonons scattering by the fluctuations of the magnetic (and the structural) order parameter. The magnetic field suppresses fluctuations, increases thermal conductivity and shifts the critical temperature towards high T. In the behavior of κ(T) and η(T) around TS = 200 K for the composition with x = 0.175 the are anomalies observed associated with a structural transition from the rhombohedral (R) to the orthorhombic (O*) phase. The anomaly observed in the κ(T) dependence in antiferromagnet LaMnO3 near TN is associated with the presence of the magnetic contribution to thermal conductivity.