Effect of Nb substitution for V on the thermoelectric properties of Fe2VAl

Abstract: In order to clarify the substitution effect of Nb for V on the thermoelectric properties of Heusler-type Fe2VAl, we prepared the polycrystalline samples of Fe2V1−x Nb x Al (x =0, 0.05, 0.1, and 0.2) and the electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) were investigated. The samples with x =0 and 0.05 were the Heusler-type single phase, while other samples contained a small amount of impurity phases. The Fe2V0.95Nb0.05Al and the Fe2V0.9Nb0.1Al samples as well as the Fe2VAl sample exhibited relatively high power factor (S 2 ρ −1) values (>10−3 Wm−1 K−2 at around room temperature), while that of the Fe2V0.8Nb0.2Al sample was fairly low. The Nb-substituted Fe2VAl samples indicated lower κ values than that of the Fe2VAl sample, indicating that the effective phonon scattering due to the fluctuation effects between V and Nb occurred in the present system. [Copyright &y& Elsevier]