Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound
Improvement of p-type thermoelectric performance for Heusler-type Fe2V1.08−yTiyAl0.92 alloys with y = 0–0.34 has been investigated, focusing on the valence electron concentration (VEC) effect for tuning the Fermi level across the center of the pseudogap via Ti doping, combined with a constructive mo...
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2019-12-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/1.5123783 |
| _version_ | 1819034457160548352 |
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| author | Y. Nishino S. Kamizono H. Miyazaki K. Kimura |
| author_facet | Y. Nishino S. Kamizono H. Miyazaki K. Kimura |
| author_sort | Y. Nishino |
| collection | DOAJ |
| description | Improvement of p-type thermoelectric performance for Heusler-type Fe2V1.08−yTiyAl0.92 alloys with y = 0–0.34 has been investigated, focusing on the valence electron concentration (VEC) effect for tuning the Fermi level across the center of the pseudogap via Ti doping, combined with a constructive modification of the electronic structure around the pseudogap through the off-stoichiometric V/Al composition change. The Seebeck coefficient changes its sign from negative to positive at around VEC = 6.0 due to Ti doping, and the peak value reaches approximately 120 μV/K at 350 K for y = 0.22. As a result of a drastic reduction in the electrical resistivity at 300–600 K, the power factor enhances up to 3.7 × 10−3 W/mK2 at 300 K for y = 0.30. The thermal conductivity increases with Ti doping to 15.5 W/mK at 350 K for y = 0.16, because of an increased stability of the L21 structure for VEC closer to 6.0, but then decreases to approximately 12 W/mK for y = 0.34. While the dimensionless figure of merit ZT = 0.13 is achieved at 500 K for y = 0.34, the codoping of Ta (Fe2V0.69Ti0.34Ta0.05Al0.92) leads to a further enhancement of up to ZT = 0.18 at 500 K. |
| first_indexed | 2024-12-21T07:34:02Z |
| format | Article |
| id | doaj.art-9eb24e6a3e7c41c19e49e6ee3a5c6931 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-21T07:34:02Z |
| publishDate | 2019-12-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-9eb24e6a3e7c41c19e49e6ee3a5c69312022-12-21T19:11:30ZengAIP Publishing LLCAIP Advances2158-32262019-12-01912125003125003-710.1063/1.5123783Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compoundY. Nishino0S. Kamizono1H. Miyazaki2K. Kimura3Department of Physical Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, JapanDepartment of Physical Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, JapanDepartment of Physical Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, JapanDepartment of Physical Science and Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, JapanImprovement of p-type thermoelectric performance for Heusler-type Fe2V1.08−yTiyAl0.92 alloys with y = 0–0.34 has been investigated, focusing on the valence electron concentration (VEC) effect for tuning the Fermi level across the center of the pseudogap via Ti doping, combined with a constructive modification of the electronic structure around the pseudogap through the off-stoichiometric V/Al composition change. The Seebeck coefficient changes its sign from negative to positive at around VEC = 6.0 due to Ti doping, and the peak value reaches approximately 120 μV/K at 350 K for y = 0.22. As a result of a drastic reduction in the electrical resistivity at 300–600 K, the power factor enhances up to 3.7 × 10−3 W/mK2 at 300 K for y = 0.30. The thermal conductivity increases with Ti doping to 15.5 W/mK at 350 K for y = 0.16, because of an increased stability of the L21 structure for VEC closer to 6.0, but then decreases to approximately 12 W/mK for y = 0.34. While the dimensionless figure of merit ZT = 0.13 is achieved at 500 K for y = 0.34, the codoping of Ta (Fe2V0.69Ti0.34Ta0.05Al0.92) leads to a further enhancement of up to ZT = 0.18 at 500 K.http://dx.doi.org/10.1063/1.5123783 |
| spellingShingle | Y. Nishino S. Kamizono H. Miyazaki K. Kimura Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound AIP Advances |
| title | Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound |
| title_full | Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound |
| title_fullStr | Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound |
| title_full_unstemmed | Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound |
| title_short | Effects of off-stoichiometry and Ti doping on thermoelectric performance of Fe2VAl Heusler compound |
| title_sort | effects of off stoichiometry and ti doping on thermoelectric performance of fe2val heusler compound |
| url | http://dx.doi.org/10.1063/1.5123783 |
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