In continuation of our systematic study of the options of the development of high-performance thermal barrier coatings based on three-component ceramic materials comprising rare-earth oxides, we report on the effects of component concentrations on the thermophysical properties of ceramics based on the Sm2O3-ZrO2-HfO2 system. Samarium oxide is found to stabilize these ceramics when its concentration is higher than 22.5 mol % and zirconium oxide concentration is lower than 56.7 mol %. The temperature coefficient of linear expansion (TCLE) of the studied ceramic materials in the temperature range 20-1400 degrees C can reach alpha(L) = (10.4 +/- 0.6) x 10(-6) with acceptable values of the thermal conductivity coefficient at a level of 0.56-0.84 W/(m K).