Preparation of the crack-free single phase (Zn1–xCdx)13Sb10 by a gradient freeze method and their structural and thermoelectric properties

Structural and thermoelectric properties have been investigated for (Zn1−xCdx)13Sb10 compounds prepared by a gradient freeze method. The crack-free single phase of the (Zn1−xCdx)13Sb10 was obtained with the starting Cd composition up to x = 0.4. The large distribution of the chemical composition has been elucidated along the growth direction in the ingots prepared; Cd is poor in the lower part of the ingots, while the chemical composition is nearly the same as the starting one in the upper part. The lattice constants increase with increasing Cd content. The Seebeck coefficient and electrical resistivity are enhanced, whereas the thermal conductivity is strongly decreased by 20% by the Cd substitution, leading to the enhancement of the dimensionless figure of merit by 10% at x = 0.30 at 340 K.