Thermoelectric properties of La filled skutterudite prepared by mechanical alloying and hot pressing

LayFexCo4−xSb12 skutterudites with different La filling content (y = 0.2, 0.4, 0.6, 0.9; x = 1.0) were prepared by mechanical alloying and hot pressing. The effect of La partially filling on the thermoelectric properties of these compounds has been studied. The results showed that the LayFexCo4−xSb12 single phase skutterudite compounds could be obtained by a combination of a 10 h mechanical alloying and a subsequent hot pressing at 650 °C for 2 h. Electrical and thermal conductivities of La filled skutterudite LayFeCo3Sb12 decreased with increasing La filling fraction. The Seebeck coefficient of LayFeCo3Sb12 became negative when y is 0.9. The figure of merit Z increased with La filling when the La content was not too high. The value Z of La0.6FeCo3Sb12 is larger than the other filled skutterudite compounds.