Low temperature calorimetric, magnetic, and optical studies of dysprosium sesquisulfide

Heat capacity, magnetic susceptibility, and optical measurements have been made on γ-Dy2S3 having the Th3P4 bcc defect-type structure. The compound remains paramagnetic down to 2 K, the lowest temperature of measurements. A heat capacity anomaly with its peak at 3.3 K can be interpreted using the Stark levels of the ground state manifold 6H15/2(4f9) of Dy+3 obtained from optical spectra. By subtracting the corresponding Schottky term from the total heat capacity, the lattice contribution is estimated. By further analyzing the temperature dependence of this contribution, in comparison with those for diamagnetic Y2S3, La2S3, and Lu2S3, the limiting Debye temperature value of Dy2S3 is found to be 290 K.