抄録
We report on the thermoelectric properties of Fe2-x(V1+x-yTiy)Al alloys (−0.04≤x≤0.02, 0≤y≤0.10). While a small deviation from the stoichiometric Fe2VAl composition causes an enhancement in the Seebeck coefficient, a slight substitution of Ti for V leads to a further increase in the Seebeck coefficient and a decrease in the electrical resistivity. The Seebeck coefficient reaches 110 μV/K at 300 K for x=−0.04 and y=0.03, which is the largest in the p-type Fe2VAl-based alloys so far reported. The electronic structures of Fe2-xV1+xAl alloys with x=−0.04, 0 and 0.02 have been investigated by soft X-ray photoelectron spectroscopy. The valence-band spectra near the EF of Fe-rich alloy (x=−0.04) is drastically changed from that of the stoichiometric Fe2VAl. Therefore substantial enhancements in the Seebeck coefficient for the off-stoichiometric alloys could be due to a modification in the band structure on the valence band side around the Fermi level EF.
