Effect of Cr and Fe Substitution on the Transport Properties of the Nowotny Chimney–Ladder MnSi δ (1.73 < δ < 1.75) Compounds

Abstract

Manganese silicides MnSi δ (1.73 < δ < 1.75) have been substituted with substantial amounts of Cr (<25%) and Fe (<30%) at the Mn site to study the resistivity (ρ), Seebeck (α) and Hall coefficients, and thermal conductivity of the resulting compositions. Only marginal reduction in ρ is observed upon substituting Cr to as much as 25%. Surprisingly, the Seebeck coefficient is positive even after substituting Fe to 20%. The Hall coefficients are positive, and the carrier concentrations seem to be less sensitive to substitution by either Cr or Fe. The promising aspect of this system is the low lattice thermal conductivity, which is approximately 2.5 W/m K at 300 K for most compositions.