Thermophysical properties of sulfides of lanthanum, praseodymium, gadolinium, and dysprosium

The temperature dependence of the thermal conductivity, electrical conductivity, thermoelectromotive force, and thermal expansion coefficient for sulfides of lanthanum, gadolinium, praseodymium and dysprosium of the composition $\mathrm{Ln}_{3-x}\mathrm{V}_x\mathrm{S}_4$ is investigated in the temperature range from $300$ to $1200$ K. It is shown that the transfer phenomena and thermoelectrical properties of the investigated compositions depend on the concentration of current carriers, cation vacancies, and mobility. Gadolinium sulfide is found to have the highest thermoelectrical efficiency. The scattering from ions of rare-earth elements has a noticeable effect on the magnitude and temperature dependence of the lattice thermal conductivity and electrical resistance.