Glass-like thermal conductivity of Nd_(2/3_x)Li_(3x)TiO_3 bulk ceramics with nanochessboard superlattice structure

摘要

We report the thermal conductivity of bulk Nd(2/3_x)Li_(3x)TiO_3 (0.047 < x < 0.151) ceramics, prepared by a conventional solid-state reaction method. These materials possess a nanochessboard superlattice structure present in every crystallite, with a superperiodicity of ~4 nm along the [110] orientation. A glass-like low thermal conductivity (1-2 W/(mK)) was shown in the Nd(2/3 -x)Li_(3X)TiO_3 system and it was almost temperature independent. Moreover, a shorter periodic length of the superlattice structure caused a lower thermal conductivity due to the increased interface phonon scattering. The low thermal conductivity is not always seen in oxide materials. In combination with the tunability of the electrical properties and the maintainability of the microstructure, we believe that this work provides an insight into the nanostructure design for the development of novel oxide thermoelectric materials.