Thermal and transport properties of manganites Nd1-xSrxMnO3Nd1-xSrxMnO3 (x=0.5x=0.5, 0.45)

The temperature dependencies of the specific heat, thermal diffusivity and thermal conductivity in polycrystalline Nd0.55Sr0.45MnO3Nd0.55Sr0.45MnO3 and Nd0.5Sr0.5MnO3Nd0.5Sr0.5MnO3 manganites are measured in wide temperature range of 77–300 K. These characteristics reveal peculiarities at magnetic phase transition and transition into charge-ordered (CO) state. It is shown that a change of the phonon spectrum due to lattice contraction is the main reason of a sharp decrease of the thermal conductivity in Nd0.5Sr0.5MnO3Nd0.5Sr0.5MnO3 at the transition to the antiferromagnetic CO state. Using the experimental thermal diffusivity data and sound velocity data a temperature dependency of the phonon mean free path is calculated.