Publications

Thermoelectric Half-Heusler compounds TaFeSb and Ta <sub>1-x</sub> Ti <sub>x</sub> FeSb (0 ≤ x ≤ 0.11): Formation and physical properties

Author(s)
A. Grytsiv, V. V. Romaka, N. Watson, G. Rogl, H. Michor, B. Hinterleitner, S. Puchegger, E. Bauer, P. Rogl
Abstract

We report on the formation, physical-chemical, as well as elastic and mechanical properties of the novel Half-Heusler (HH) compound TaFeSb that forms during a solid-state reaction from TaSb

2

and TaFe

2

in the temperature range between 800 and 850 °C. TaFeSb behaves as a semiconductor, and changes the conductivity type either on temperature or composition. Transport properties of TaFeSb and Ta

1-x

Ti

x

FeSb (0 ≤ x ≤ 0.11) were measured in the temperature range from 4.2 to 823 K, and the effect of titanium on thermoelectric and mechanical properties of Ta

1-x

Ti

x

FeSb was investigated. The Ta/Ti substitution results in a significant increase of the thermoelectric power factor to exciting values of above 6 mW/m⋅K

2

. In combination with a suppressed phonon thermal conductivity, due to a unique role of Ti, an enhanced figure of merit, ZT

900K

=1.0 (for Ta

0.94

Ti

0.06

FeSb) is obtained, close to the highest values reported for Hf-free p-type HH-systems. In addition, experimental results obtained in this study are discussed and analyzed in the context of ab-initio Density Functional Theory (DFT) calculations.

Organisation(s)
Department of Materials Chemistry, Faculty Center for Nano Structure Research
External organisation(s)
Christian Doppler Laboratory for Thermoelectricity, Lviv Polytechnic National University, Technische Universität Wien, Universität Wien
Journal
Intermetallics
Volume
111
ISSN
0966-9795
DOI
https://doi.org/10.1016/j.intermet.2019.04.011
Publication date
08-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
Physical chemistry
Keywords
ASJC Scopus subject areas
, , , ,
Portal url
https://ucris.univie.ac.at/portal/en/publications/thermoelectric-halfheusler-compounds-tafesb-and-ta-1x-ti-x-fesb-0--x--011-formation-and-physical-properties(8f32964b-186b-4873-a511-3c4a38c3d837).html