The structure of a new nano-phase of lanthanum-doped strontium titanate

Abstract

A novel ordered phase in La-doped SrTiO3 was determined through three-dimensional electron diffraction studies. An overall stoichiometry of LaSr7Ti8O23 leads to a monoclinic structure with layers of square pyramids of TiO5 localised near the lanthanum substituted positions. The difference in crystal structure of the nanoprecipitates, particularly the connection of the rigid Ti–O frameworks, should affect the phonon interactions in the bulk material and so helps to explain a decrease in the lattice thermal conductivity in the La-doped SrTiO3, which is beneficial towards desired thermoelectric properties.