Heavy-element dependence of thermoelectric properties in Fe_2 Val thin films

摘要

Heusler-type Fe_2VAl-based compoundsconsisting ofnon-toxic and abundantmaterials have been widely investigated as one of the most promising thermoelectric materials.Although its power factorreaches 5.5 mWm~(-1)K~(-2)which is even larger than that of Bi2Te3-basedthermoelectric materials, the figure of merit is still much less than unity due to the highlatticethermal conductivityof more than 20 W m~(-1)K~(-1).As forthat, we tried toreduce the thermal conductivity through two approaches,doping control usingheavy elementsandfabricating thin filmswhich successfully decreased to 7.2 and12.6Wm~(-1)K~(-1), respectively.In the present study,we intended toenhance the thermoelectric propertiesby dopingTa inin the Fe2VAl-based thin films, that is, bycombining the both approaches.