Thermoelectric properties of p-type Cr doped MnSiγ prepared by liquid quenching technique

Abstract

In this work, higher manganese silicide (HMS) with partial substitution of Cr for Mn has been studied. The Cr substitution was used to tune the carrier concentration for obtaining optimized thermoelectric properties. In order to have a wide range of carrier concentration, we employed liquid quenching technique, because the rapid quenching increases the solubility of Cr in HMS. The maximum solubility of 11 at.% Cr at Mn site in HMS was achieved in this study. The hole concentration increases with increasing Cr concentration, with that minimum electrical resistivity of 1 mΩcm was observed for Mn25.3Cr11Si63.9. The power factor was decreased with increasing Cr concentration due to reduction in Seebeck coefficient, but further addition of Cr showed increasing tendency for power factor. The maximum power factor of 1.5 mWm-1K-2 with ZT of 0.4 was obtained at 700 K for Mn25.3Cr11Si63.9.