Effect of Ba filling fraction on thermoelectric properties ofp-type Ba_yFe_1.6Co_2.4Sb₁₂

Abstract

Effects of Ba filling fraction on the thermoelectric properties of p-type filled skutterudite compounds Ba_yFe_1.6Co_2.4Sb₁₂ (y=0−0.63) were investigated. Ba_yFe_1.6Co_2.4Sb₁₂ showed p-type conduction. The hall coefficient (R_h) and seebeck coefficient (α) increased with increasing Ba filling fraction. But hole concentration (p) and electrical conductivity (σ) decreased. While Ba filling fraction was about 0.4, the lattice thermal conductivity (k_L) reached the minimum value. The results show that effect of Ba rattling on phonon scattering is the strongest as Sb-icosahedron partial voids are filled by Ba. A maximum dimensionless thermoelectric figure of merit (ZT) value of 0.7 was obtained for Ba_0.38Fe_1.6Co_2.4Sb₁₂ at 750 K.

Keywords

filled skutterudite compound / filling fraction / thermoelectric properties

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