Nanostructures and Defects in Non-equilibrium Synthesized Filled Skutterudite CeFe4Sb12

TL;DR

This study investigates the nanostructures and defects in non-equilibrium synthesized CeFe4Sb12 skutterudite, revealing nanoprecipitates, superlattices, and interface defects that influence material strain and properties.

Contribution

It provides detailed TEM analysis of nanoprecipitates and defects in CeFe4Sb12, highlighting their structures, compositions, and strain effects, which were not previously characterized in this material.

Findings

Nanoprecipitates are mostly spherical and Sb-rich.

Superlattices with ~3.576 nm periodicity are formed by Sb atom ordering.

Defects at precipitate-matrix interfaces affect strain distribution.

Abstract

We studied nanoprecipitates and defects in p-type filled skutterudite CeFe4Sb12 prepared by non-equilibrium melt-spinning plus spark plasma sintering method using transmission electron microscopy. Nanoprecipitates with mostly spherical shapes and different sizes (from several nm to several tens of nm) have been observed. The most typically observed nanoprecipitates are shown to be Sb-rich. Superlattices with a periodicity of about 3.576 nm were induced by the ordering of excessive Sb atoms along the c direction. These nanoprecipitates usually share coherent interfaces with the surrounding matrix and induce anisotropic and strong strain fields in the surrounding matrix. Nanoprecipitates with compositions close to CeSb2 are much larger in size (~ 30 nm) and have orthorhombic structures. Various defects were typically observed on the interfaces between these nanoprecipitates and the matrix. The strain fields induced by these nanoprecipitates are less distinct, possibly because part of the strains has been released by the formation of defects.