Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555
The Heusler-type Fe2VAl-based compounds can be a possible candidate for new thermoelectric materials. A significant enhancement in the Seebeck coefficient with both positive and negative sign can be achieved not only by the Fe/V off-stoichiometry combined with doping but also by the V/Al off-stoichiometry even without doping. For the latter alloys, the peak temperature of the Seebeck coefficient increases up to 600 K, and the maximum power factor is 4.3× 10-3 for p-type and 6.8× 10-3 W/mK2 for n-type, both of which are higher than those of the half-Heusler compound ZrNiSn and Mg2Si compound. A large power factor is required for practical applications of automotive thermoelectric generators. The heavy element Ta doping for the V/Al off-stoichiometric alloys is effective in increasing the dimensionless figure of merit at around 500 K.
Heusler compound, Fe2VAl, pseudogap, off-stoichiometry, valence electron concentration, thermoelectric materials
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