Synthesis, crystal structure, and thermoelectric properties of the YbAl3-ScAl3 solid solution

The Yb1−xScxAl3 alloy solid solution has been successfully synthesized for 0 ≤ x ≤ 1 by a combination of arc melting, pulverization, and consolidation by pulsed electric current sintering. The thermoelectric properties of the alloys have been investigated over the temperature range 80–300 K. Our results on pure YbAl3 confirm previous studies demonstrating the combination of low electrical resistivity (∼100 μΩ cm) and large Seebeck coefficient (∼85 μV K−1) at 300 K. With increasing values of x the alloys become even more metallic, but the Seebeck coefficient decreases more gradually than the resistivity, resulting in enhanced thermoelectric power factor for 0 ≤ x ≤ 1. An increase in electronic thermal conductivity is partially offset by a strong suppression in lattice thermal conductivity that arises due to alloy scattering. As a result, the thermoelectric figure of merit of alloys with x = 0.25 is increased by 30% relative to YbAl3 at 250 K.