Published online by Cambridge University Press: 01 February 2011
We report transport properties of polycrystalline TMGa3 (TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017 - 1018cm−3. Seebeck coefficient measurements reveal that FeGa3 is n -type material, while the Seebeck coefficient of RuGa3 changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1 at room temperature and decreased to 2.5Wm−1K−1 for FeGa3 and 2.0Wm−1K−1 for RuGa3 at high temperature. The resulting thermoelectric figure of merit, ZT, at 945K for RuGa3 reaches 0.18.