Effect of filling atoms onlattice thermal conductivity of Ln_yFe_xCo_4-xSb₁₂(Ln=Ce, Ba, Y)

X. F. Tang¹, L. D. Chen²,T. Goto³, T. Hirai³, R. Z. Yuan¹

¹State Key Laboratory ofAdvanced Technology for Materials Synthesis and Processing, Wuhan University ofTechnology, Wuhan 430070, China

²State KeyLaboratory of High Performance Ceramics and Superfine Structure, ShanghaiInstitute of Ceramics, CAS, Shanghai 200050, China

³Institute for MaterialsResearch, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan

Ce, Ba or Y were chosen as thefiller atom. Effects of kind of filling atom and filling fraction on latticethermal conductivity of Ln_yFe_xCo_4-xSb₁₂(Ln=Ce, Ba, Y) were investigated. Lattice thermal conductivity of Ln_yFe_xCo_4-xSb₁₂decreased significantly with an increasing Ce, Ba or Y filling fractionin the Sb-icosahedron voids. Lattice thermal conductivity of Ce or Ba filled(Ce, Ba)_yFe_xCo_4-xSb₁₂ have peakvalues at about 40K, and show thermal conductivity characteristic of thecrystal. The peak values of lattice thermal conductivity of Y filled Y_yFe_xCo_4-xSb₁₂was not observed, indicating that Y_yFe_xCo_4-xSb₁₂shows a thermal conductivity characteristic of a glass. Y was more effectivethan Ce or Ba. To decrease the lattice thermal conductivity of filledskutterudite compounds Lattice thermal conductivity of Ln_yFe_xCo_4-xSb₁₂ reached a minimum values atcertain filling fraction, indicating that rattling effect of filling atoms wasthe strongest at certain filling fraction.