On the thermoelectric and magnetic properties, hardness, and crystal structure of the higher boride YbB66
| Autor: | P. Sauerschnig, Kantaro Tsuchiya, Shu Yin, Toetsu Shishido, Oksana Sologub, Yuichi Michiue, Akira Yoshikawa, Takaho Tanaka, Toshiyuki Mori |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Condensed matter physics Mechanical Engineering Metals and Alloys 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Thermoelectric materials 01 natural sciences Variable-range hopping Magnetic susceptibility 0104 chemical sciences chemistry.chemical_compound chemistry Mechanics of Materials Electrical resistivity and conductivity Boride Seebeck coefficient Thermoelectric effect Materials Chemistry 0210 nano-technology Single crystal |
| Zdroj: | Journal of Alloys and Compounds. 813:152182 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2019.152182 |
| Popis: | In this work we report the results of our investigation of YbB66 as a potential high-temperature thermoelectric material. A high-quality single crystal has been grown by the optical floating zone method. Thermoelectric transport properties were measured in a temperature range of 373–973 K YbB66, like REB66 compounds in general, is a p-type semiconductor whose electrical properties can be described by Mott's variable range hopping mechanism. It shows very large Seebeck coefficient ranging from 588 μV K−1 at 373 K to 241 μV K−1 at 973 K and an electrical resistivity ρ that decreases by almost 4 orders of magnitude from 9.4×10−1 Ω m to 2.4 × 10−4 Ω m. Together with the low thermal conductivity of 2.6 W m−1 K−1 a maximum ZT close to 0.1 around 1000 K was determined with trend of sharp increase toward higher temperatures, which is similar to the previous report of SmB66, and significantly larger than previously reported for Y and Er phases of REB66. However, unlike SmB66, the effective magnetic moment suggests a trivalent state for Yb instead of mixed valence, which was determined by measuring the magnetic susceptibility from 2 to 300 K. The composition of YbB66 was indicated to be metal-rich, which actually may be the origin of the good performance. |
| Databáze: | OpenAIRE |
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