Structural and thermoelectric characterizations of samarium filled CoSb3 skutterudites

Abstract Sm filled CoSb 3 without charge compensation was synthesized at ambient pressure for the first time through a melt-annealing method. The synthetic Sm y Co 4 Sb 12 samples possess an Im 3 ¯ symmetry of skutterudite structure. The lattice parameter expanded mildly after Sm inclusion into CoSb 3 lattice. A larger atomic displacement parameter (ADP) was revealed for Sm atoms compared with those of Co and Sb atoms, indicating the rattling mode of Sm atoms inside the oversized cages. The thermoelectric property investigations revealed a significantly depressed thermal conductivity caused by the strong phonon scattering from loosely bond Sm fillers while maintaining high electrical performance. As a result, the maximum ZT value of 0.8 was achieved at 716 K for Sm 0.6 Co 4 Sb 12 sample.