THE THERMAL AND ELECTRIC PROPERTIES OF LANTHANUM SULFIDES WITH SAMARIUM ADMIXTURES AT HIGH-TEMPERATURES

The temperature dependence of the thermal conductivity, coefficient of thermal expansion, electrical conductivity, thermoelectromotive force of LaSx solid solutions (x = 1.48, 1.46, 1.443), and of the LaS1.48 c omposition with admixtures of 0.5 and 1 at. % Sm is investigated withi n the temperature range 300 - 1300 K. It is shown that the magnitude a nd temperature dependence of the parameters studied are defined by the concentration of cation vacancies in the lanthanum sublattice, as wel l as by the variation in the elastic parameters of the lattice as a re sult of the samarium admixture. The thermoelectric efficiency (Z) is e stimated. At temperatures above 1000 K, the value of Z proved to be hi gher than those for the known high-temperature materials prepared on t he basis of Si-Ge. At 1200 K for LaSi1.48 + 0.5 at. % Sm, Z = 0.8 x 10 (-3) K-1.