Phase stability and thermoelectric properties of TiCoSb-TiM2Sn (M = Ni, Fe) Heusler composites
Year: 2019
Type: article
Abstract: Heusler composites have attracted significant attention as a new route towards improving the thermoelectric figure of merit (ZT) through reduction of the lattice thermal conductivity and carrier filtering effects. This work extends this field by investigating TiCoSb-TiM 2 Sn (M = Ni, Fe) composites. All end-members are stable phases but no clean segregation into half- and full-Heusler phases was observed. Instead, for M = Ni, partial substitution on the Co sublattice and n-type doping occurs, combined with the formation of Ni 3 Sn 2 and full-Heusler phases. For M = Fe, substitution on the Co site occurs, leading to p-type conduction. Rietveld analysis of neutron powder diffraction data reveals no evidence for the presence of metals on the vacant tetrahedral site, signalling the absence of embedded Heusler inclusions. The thermoelectric properties of both series vary systematically with composition. For both n-type (M = Ni) and p-type (M = Fe) series, the highest measured power factors S 2 /ρ ∼ 0.8 mW m −1 K −2 leading to ZT ∼ 0.12 at 713 K. This work extends knowledge regarding the phase stability and thermoelectric properties of TiCoSb-based Heusler composites.
Source: Journal of Solid State Chemistry
Authors: M. Asaad, J. Buckman, R.I. Smith, J.-W.G. Bos
Institutions: Heriot-Watt University, Rutherford Appleton Laboratory
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,200
OpenAlex ID: W2944704568