Elevation of the power factor of Co₄Sb₁₂ skutterudite with Sm-doping in high-pressure high-temperature synthesis

A thermoelectric material Sm_xCo₄Sb₁₂ (0 < x < 1.0) is synthesized at high pressure and high temperature leading to an enhanced power factor. The experimental measurements show that the Sm _xCo₄Sb₁₂ compounds exhibits n-type conduction. The absolute value of the Seebeck coefficient decreases with increasing Sm fraction. The resistivity increases with samarium content x from 0.1 to 0.2, but decreases dramatically when x changes from 0.2 to 1.0. The maximum power factor reaches 13.1 μWcm^-1 K^-2 at x 1.0, which is larger than the data previously reported for the La-doped CoSb₃ prepared at room pressure.