Thermoelectric Half-Heusler compounds TaFeSb and Ta _1-x Ti _x FeSb (0 ≤ x ≤ 0.11): Formation and physical properties

Autor(en)

A. Grytsiv, V. V. Romaka, N. Watson, G. Rogl, H. Michor, B. Hinterleitner, S. Puchegger, E. Bauer, P. Rogl

Abstrakt

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(en)

Institut für Materialchemie, Fakultätszentrum für Nanostrukturforschung

Externe Organisation(en)

Christian Doppler Laboratory for Thermoelectricity, Lviv Polytechnic National University, Technische Universität Wien, Universität Wien

Journal

Intermetallics

Band

111

ISSN

0966-9795

DOI

https://doi.org/10.1016/j.intermet.2019.04.011

Publikationsdatum

08-2019

Peer-reviewed

Ja

ÖFOS 2012

Physikalische Chemie

Schlagwörter

ASJC Scopus Sachgebiete

, , , ,

Link zum Portal

https://ucris.univie.ac.at/portal/de/publications/thermoelectric-halfheusler-compounds-tafesb-and-ta-1x-ti-x-fesb-0--x--011-formation-and-physical-properties(8f32964b-186b-4873-a511-3c4a38c3d837).html