Thermoelectric properties of rare-earth doped Fe2VAl Heusler alloys

The low-temperature electrical transport properties of the rare-earth (RE) Ce, Dy, Sm element doped Fe2VAl Heusler alloys have been investigated. A significant enhancement in the Seebeck coefficient S (peak values of about -125 to -160 mu V K-1) is observed as compared to the pure Fe2VAl (peak value of about 40 mu V K-1). It is observed that the thermal conductivity reduced by 50% in RE-doped samples. The single parabolic band model has been used to analyze the experimental data and to understand the role of fundamental parameters like the Lorenz number. The lattice contribution to the total thermal conductivity was analyzed through the Callaway model, which in turn provided the insight into the phonon scattering in these alloys. Finally, we demonstrate a significant improvement in power factor and figure of merit at all temperatures for the RE-doped Fe2VAl alloys.