Thermoelectric Properties of P-type Half-Heusler Compounds HfPtSn and ZrPtSn
Thermoelectric Properties of P-type Half-Heusler Compounds HfPtSn and ZrPtSn
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DOI：
10.1109/ict.2006.331294
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
Y. Kimura;A. Zama;Y. Mishima
中科院分区：
文献类型：
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作者：
Y. Kimura;A. Zama;Y. Mishima
我们重点关注半霍斯勒化合物 MPtSn，其中 M 为 Hf、Zr 和 Ti，寻找在高达 1000 K 左右的宽温度范围内本质上表现出优异的 p 型热电性能的半霍斯勒化合物。采用光学浮区熔化法通过定向凝固制备了近单相 MPtSn 合金，以尽可能正确地评估热电性能。我们发现 HfPtSn 和 ZrPtSn 在 300 至 1100 K 的测量温度范围内表现出 p 型热电性能，正如我们之前的工作所预期的那样。有趣的是，价电子数相同为 18 的 HfNiSn 和 ZrNiSn 都表现出 n 型热电特性。 HfPtSn 在低温和中温范围内显示出相当高的 p 型热电势值，约为 250 muV/K，而 ZrPtSn 显示出较小的最大值，约为 70 muV/K。另一方面，TiPtSn 在环境温度下表现出非常大的 n 型热电势，约为 500 muV/K，尽管它在高温下急剧下降。高电阻率是所有三种 MPtSn 化合物的共同主要缺点。 HfPtSn 的热导率在 MPtSn 中最低，但值相对较高。由于高电阻率和低载流子浓度（测量值为 2.17 乘以 1025 m-3），晶格贡献被认为在热传导中占主导地位
We focused on half-Heusler compounds MPtSn, where M is Hf, Zr and Ti, to seek for half-Heusler compounds which intrinsically show excellent p-type thermoelectric properties in a wide temperature range up to around 1000 K. Nearly single-phase MPtSn alloys were fabricated by directional solidification using optical floating zone melting method to evaluate thermoelectric properties as properly as possible. We have found that HfPtSn and ZrPtSn show p-type thermoelectric properties in a measured temperature range from 300 to 1100 K as it is expected from our previous work. It is interesting that HfNiSn and ZrNiSn with the same valence electrons count of 18 are well-known to show n-type thermolectric properties. HfPtSn shows quite high values of p-type thermoelectric power around 250 muV/K in low and intermediate temperature ranges, while ZrPtSn shows much smaller maximum value of about 70 muV/K. On the other hand, TiPtSn exhibits very large n-type thermoelectric power of around 500 muV/K at ambient temperatures though it decreases drastically at elevated temperatures. High electrical resistivity is a major drawback that all three MPtSn compounds have in common. HfPtSn has the lowest thermal conductivity among MPtSn though the values are relatively high. The lattice contribution is supposed to dominates the thermal conduction because of high electrical resistivity and low carrier concentration measured as 2.17 times 1025 m-3