JINSTMET : Vol. 72 (2008) , No. 8 pp.593-598

p 型 Fe₂(V_1-x-yTi_xTa_y) Al 合金の熱電特性

1) 名古屋工業大学大学院工学研究科物質工学専攻

(Received March 24, 2008)
(Accepted April 30, 2008)

We report on the temperature dependence of the electrical resistivity and the Seebeck coefficient for the p-type Fe₂(V_1-x-yTi_xTa_y)Al alloys with compositions 0≤x≤0.10 and 0≤y≤0.10, in addition to the composition dependence of the thermal conductivity at room temperature. While Fe₂VAl (x=0, y=0) exhibits a semiconductor-like behavior in the electrical resistivity, a slight doping of Ti and Ta causes a significant decrease in the resistivity at low temperature and a large enhancement in the Seebeck coefficient, reaching 90 μV/K for x=0.03 and y=0.10. The power factor is found to be substantially larger than that for the p-type Fe₂(V_1-xTi_x)Al alloys so far reported. Although the thermal conductivity for Fe₂(V_1-xTi_x)Al remains in the range of 24∼28 W/mK for 0≤x≤0.10, it decreases significantly with the Ta substitution, reaching 11∼12 W/mK for 0≤x≤0.10 and y=0.10. We conclude that doping of heavier atoms such as Ta reduces more effectively the lattice thermal conductivity.

Keywords:

thermal conductivity, power factor, thermoelectric properties, pseudogap, Heusler alloys