Enhancement of thermoelectric properties of off-stoichiometric Heusler compounds and elucidation of its mechanism

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420664
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: NISHINO Yoichi 名古屋工業大学, 工学(系)研究科(研究院), 教授 (50198488)
• Co-Investigator(Renkei-kenkyūsha): MIYAZAKI Hidetoshi 名古屋工業大学, 大学院工学研究科, 准教授 (10548960)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 熱電変換材料 / ホイスラー化合物 / 擬ギャップ / ゼーベック効果 / 価電子濃度 / 非化学量論組成 / 電子構造 / 熱伝導率

Outline of Final Research Achievements

Off-stoichiometric Fe2V1+x-yTayAl1-x alloys are of n-type for V-rich composition (x>0) but of p-type for Al-rich composition (x<0). The n-type alloy shows the power factor reaching 5.8×10-3 W/mK2, in parallel with the possession of the thermal conductivity as low as 5.6 W/mK, because of the synergistic effect of off-stoichiometry and Ta substitution. Thus the dimensionless figure of merit leads to ZT=0.29 at 400K. In addition, the p-type alloy shows the power factor of 3.3×10-3 W/mK2 and ZT=0.13 at 350K. On the other hand, the p-type alloys derived from n-type Fe2V1+xAl1-x with Ti doping show a comparable value of the above ZT even without Ta substitution.

Free Research Field

工学