title: Phase separation as a key to a thermoelectric high efficiency.
abstract: This work elucidates the possible reasons for the outstanding, but never reproduced thermoelectric properties of the doped Ti(0.5)Zr(0.25)Hf(0.25)NiSn Heusler compounds. The structural investigations done via synchrotron X-ray diffraction measurements and scanning electron microscope measurements, which clearly show that the microstructure consists of three temperature stable C1(b) phases with possible semi-coherent interfaces, are presented. The exceptional thermoelectric properties are due to this intrinsic phase separation. It is possible to reproduce the high Figure of Merit values with ZT = 1.2 at 830 K. Furthermore, the influence of doping different elements on the Sn position in this Heusler material system is investigated.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universtität, 55099 Mainz, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schwall
authors.forename: Benjamin
authors.initials: B
authors.lastname: Balke