Sm3TaO7: Heat Capacity and Thermal Expansion

The molar heat capacity of Sm3TaO7 was determined by relaxation, adiabatic and differential scanning calorimetry in the region of 2–1350 K and the thermodynamic functions were calculated. The total contribution of the Schottky anomaly to the heat capacities of samarium tantalate was evaluated. The temperature dependences of the parameters of the orthorhombic crystal lattice of the space group C2221 in the temperature range of 300–1204 K have been determined and the coefficients of thermal expansion have been estimated. The temperature dependence of heat capacity of samarium tantalate exhibits an anomaly in the region of 1116–1275 K associated with the structural phase transition. The space group of the high-temperature orthorhombic phase Sm3TaO7 is identified as Cmcm.