Effect of Interstitial Mg in MgSi on Electrical Conductivity and Seebeck Coefficient.

The crystal structure, thermoelectric properties, and microstructure of polycrystalline samples with nominal compositions MgSi ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) have been investigated. It is revealed that the MgSi samples were composites consisting of MgSi matrix with dispersed Mg metal. The MgSi crystals contained a small amount of Mg atoms at interstitial (1/2 1/2 1/2) site (Mg). In addition, Mg metal was present at grain boundaries between MgSi crystal grains (Mg). Regarding thermoelectric properties, the electrical conductivity and Seebeck coefficient of MgSi were measured and their x dependences were discussed in terms of the amounts of Mg and Mg. The amount of Mg and the electrical conductivity indicate quite similar x dependences. [ABSTRACT FROM AUTHOR]