Effect of secondary LuNiSn phase on thermoelectric properties of half-Heusler alloy LuNiSb

TL;DR

This study investigates the thermoelectric properties of LuNiSb, LuNiSn, and their composite, revealing that the composite combines electrical conductivity and thermoelectric properties but does not improve overall performance.

Contribution

It provides new insights into the thermoelectric behavior of LuNiSb, LuNiSn, and their composite, highlighting the lack of performance enhancement in the composite material.

Findings

LuNiSn exhibits metallic conductivity.

LuNiSb shows semiconducting-like behavior.

The composite combines properties but does not enhance thermoelectric performance.

Abstract

We report on the high-temperature (350 K <T< 1000 K) thermoelectric properties of the ternary compounds LuNiSb (cubic) and LuNiSn (orthorhombic) and a composite material (LuNiSb)$_{0.5}$(LuNiSn)$_{0.5}$. The electrical conductivity in LuNiSn is metallic, while it is semiconducting-like in LuNiSb. The Seebeck coefficient reaches -5.5 $\mu$V/K at 700 K for the former compound and 66 $\mu$V/K at 607 K for the latter one. The composite sample (LuNiSb)$_{0.5}$(LuNiSn)$_{0.5}$ constructed from orthorhombic matrix with cubic inclusions combines the electrical conductivity of LuNiSn with the thermoelectric properties of LuNiSb. Nonetheless, no enhancement of the thermoelectric performance occurs for this material.