Abstract
The Heusler-type Fe2VAl compound is found to be a nonmagnetic semimetal with a sharp pseudogap at the Fermi level. Remarkably, doping of quaternary elements causes a significant decrease in the electrical resistivity and a large enhancement in the Seebeck coefficient. Since the Seebeck coefficient varies systematically with the valence electron concentration (VEC), irrespective of doping elements, the net effect of doping is most likely to cause a rigid-band-like shift of the Fermi level from the central region in the pseudogap. The Fe2VAl-based compounds are a promising candidate for thermoelectric power generation because of the possession of higher thermoelectric power factor than that of Bi-Te system. The durable thermoelectric module designed for motorcycles has successfully been fabricated, using microstructural Fe2VAl-based sintered alloys prepared by mechanical alloying and pulse-current sintering.
