[20p-234B-1~17] 22.1 Joint Session M "Phonon Engineering"

▲ [20p-234B-11] Heavy-element dependence of thermoelectric properties in Fe₂VAl thin films

〇(PC)Seongho Choi¹, Satoshi Hiroi², Dogyun Byeon¹, Masaharu Matsunami¹, Tsunehiro Takeuchi¹ (1.Toyota Tech. Inst., 2.NIMS.)

Keywords:Heusler compounds, Thin film, Time-domain thermoreflectance

Heusler-type Fe₂VAl-based compounds consisting of non-toxic and abundant materials have been widely investigated as one of the most promising thermoelectric materials. Although its power factor reaches 5.5 mWm^-1K^-2 which is even larger than that of Bi₂Te₃-based thermoelectric materials, the figure of merit is still much less than unity due to the high lattice thermal conductivity of more than 20 W m^-1K^-1. As for that, we tried to reduce the thermal conductivity through two approaches, doping control using heavy elements and fabricating thin films which successfully decreased to 7.2 and 12.6 Wm^-1K^-1, respectively.^1,2 In the present study, we intended to enhance the thermoelectric properties by doping Ta in in the Fe₂VAl-based thin films, that is, by combining the both approaches.