The thermoelectric half-Heusler compound Ti0.5(Hf0.5Zr0.5)0.5NiSn0.998Sb0.002 was fabricated by spin-casting and subsequent annealing. ZT at room temperature increased with annealing time through an increase in absolute Seebeck coefficients despite a decrease in electrical conductivity. ZT reached 0.10 after annealing at 1050 K for 48 h. In powder x-ray diffraction analysis, each half-Heusler peak was accompanied by a bump at the high-angle side, corresponding to a minor Ti-rich half-Heusler phase. The quantity and Ti composition of the minor phase increased with annealing time, although those of the major half-Heusler phase were almost constant. In transmission electron microscopic analysis, granular domains, several nanometers in size, with atomic ordering or disordering were observed. Thermoelectric properties were␣improved by annealing through the growth of heterogeneous microstructures of the Ti-rich and Ti-poor half-Heusler grains and of the granular domains.
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Morimura, T., Hasaka, M., Yoshida, S. et al. Microstructures and Thermoelectric Properties of an Annealed Ti0.5(Hf0.5Zr0.5)0.5NiSn0.998Sb0.002 Ribbon. J. Electron. Mater. 38, 1154–1158 (2009). https://doi.org/10.1007/s11664-009-0773-8
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DOI: https://doi.org/10.1007/s11664-009-0773-8