Thermoelectric Properties of Ternary Rare-Earth Copper Antimonides LaCu_xSb_2 (0.9 < = x < = 1.3)

摘要

Ternary rare-earth antimonides LaCu_xSb_2 with 0.9 < x < 1.3 were prepared by arc melting the constituents and annealing the obtained products at 973 K for 144 h. The annealed products were then consolidated by pressure-assisted sintering at 1043K for 3h. X-ray powder diffractometry showed that all the sintered samples crystallized in the tetragonal HfCuSi_2-type structure. While the lattice constant c increased with Cu content, the lattice constant a came to minimum at x = 1.0. In the temperature range 300-800 K, the Seebeck coefficients of all the samples were positive. The Seebeck coefficient and electrical resistivity were observed to increase with the temperature. The decrease in the Cu content resulted in the increase in the Seebeck coefficient and electrical resistivity, and hence improving slightly the thermoelectric power factor. However, the thermoelectric power factor was substantially smaller than that of state-of-the art thermoelectric materials,