RuIn3-xSnx, RuIn3-xZnx, and Ru1-yIn3—new thermoelectrics based on the semiconductor RuIn3

A systematic investigation of the intermetallic phase Ru1-yIn3 (0 ≤ y ≤ 0.025) and its substitution derivatives RuIn3-xSnx and RuIn3-xZnx (x = 0.01, 0.025, 0.05, and 0.1) is performed. The samples were prepared from a liquid–solid reaction of components with subsequent spark plasma sintering treatment. Ru1-yIn3 exhibits n- and p-type behavior crossing over from low to high temperatures. Substitution of indium by tin or zinc up to 2.5 at.% leads to an increase of the charge carrier concentration, with negative (Sn) or positive (Zn) Seebeck values, respectively. The electrical resistivity was P changed from semiconductor- to metal-like properties by substitution, whereas the thermal conductivity was reduced down to 50% of that of RuIn3. Higher values of the thermoelectric figure of merit were achieved by chemical substitution (RuIn3-xSnx, RuIn3-xZnx), opening up a possibility for tuning the thermoelectric properties in this class of materials.