Observation of the reduction of thermal conductivity in a p-type nanostructured half-Heusler using neutron inelastic scattering

Published

November 24, 2015

Author(s)

Winnie K. Wong-Ng, Jeffrey W. Lynn, Qingzhen Huang, Craig Brown, James A. Kaduk, Giri Joshi

Abstract

To understand the role of the nanophase in reducing the lattice contribution of the thermal conductivity of thermoelectrics, the structure and phonon density of a p-type half-Heusler thermoelectric ingot (ingot-HH, nominal composition of (Hf0.5Zr0.5)Co(Sb0.8Sn0.2)), and its nano form prepared from ball milling (nano-HH), were studied using neutron diffraction and neutron inelastic scattering techniques. They are both cubic, F-43m, with lattice parameters a= 6.0649(3) Å (nano) and 6.0629(1) Å (ingot), but the nano and ingot materials exhibit markedly different generalized phonon density-of-states (GDOS) at 300 K due to the substantially reduced grain size in the nano sample. This overall changes in GDOS, together with the increase in grain boundary scattering, account for the sharp reduction of the thermal conductivity in the nano-hot-pressed (nano-hp-HH) sample, which has a similar average grain size to that of nano-HH.

Citation

Nano Letters

Volume

107

Pub Type

Journals

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DOI Link

Keywords

Thermoelectrics, p-type half-Heusler, (Hf0.5Zr0.5)Co(Sb0.8Sn0.2), neutron diffraction, neutron inelastic scattering, GDOS

Citation

Wong-Ng, W. , , J. , Huang, Q. , Brown, C. , Kaduk, J. and Joshi, G. (2015), Observation of the reduction of thermal conductivity in a p-type nanostructured half-Heusler using neutron inelastic scattering, Nano Letters, [online], https://doi.org/10.1063/1.4936163 (Accessed October 27, 2025)