Kinetic properties and magnetic susceptibility of La0.825Sr0.175MnO3 under hydrostatic pressure.

The magnetic susceptibility χ, thermopower α, and resistivity ρ of single crystals of the manganate La_0.825Sr_0.175MnO₃ are investigated in the temperature interval 77–300 K and at pressures to 14 kbar. All of these measurements reveal the presence of a transition to a ferromagnetic metallic state at T_C≈280 K and a structural transition at T_str≈200 K. The pressure coefficients of these transition temperatures are found to be ∂T_C/∂P=+1.3 K/kbar and ∂T_str/∂P=-6.3 K/kbar. The thermopower α(T) is everywhere positive, has a domelike shape, and decreases with increasing pressure. On the χ(T) curve at T≈100 K there is a feature that is shifted to lower temperatures under pressure (∂T_M/∂P=-5.8 K/kbar). The physical cause of this feature is discussed. [ABSTRACT FROM AUTHOR]