Thermoelectric properties of UB4 from 300 to 850 K Original Research Article

Seebeck coefficient and the electrical conductivity for polycrystalline UnB (nB4: natural boron) were measured in the temperature range from 300 to 850 K. Seebeck coefficient increased with temperature from 8 μVK−1 at 300 K to 40 μVK−1 at 850 K, and the electrical conductivity decreased with increasing temperature from 2.7×103 Scm−1 at 300 K to 2.3×103 Scm−1 at 850 K. The temperature dependence of the electrical conductivity suggested that UB4 had semimetallic character. The power factor for UnB4 showed the value of 3.4×10−4 Wm−1 K−2 at 850 K. The power factor for isotopically enriched U11B4 showed the value of 7.2×10−4 Wm−1 K−2 at 850 K. It was suggested that the power factor for UB4 was enhanced by the increase in carrier concentration with impurities.