Influence of the sintering temperature on the thermoelectric properties of the Bi$_{1.9}$Gd$_{0.1}$Te$_{3}$ compound

The regularities of the influence of the sintering temperature (750, 780, 810, and 840 K) on the elemental composition, crystal-lattice parameters, electrical resistivity, Seebeck coefficient, total thermal conductivity, and thermoelectric figure of merit of the Bi$_{1.9}$Gd$_{0.1}$Te$_{3}$ compound are investigated. It is established that the elemental composition of the samples during high-temperature sintering varies due to intense tellurium evaporation, which can lead to the formation of various point defects (vacancies and antisite defects) affecting the majority carrier (electron) concentration and mobility. The sintering temperature greatly affects the electrical resistivity of the samples, while the influence on the Seebeck coefficient and total thermal conductivity is much weaker. The largest thermoelectric figure of merit ($ZT\approx$ 0.55) is observed for the sample sintered at 750 K.