论文标题
热电参数对Mn取代的Fe2cral Heusler合金中载体浓度和电子结构的异常依赖性
Anomalous dependence of thermoelectric parameters on carrier concentration and electronic structure in Mn-substituted Fe2CrAl Heusler alloy
论文作者
论文摘要
我们研究了Heusler合金Fe2-Xmnxcral（0 <x <1）的高温热电特性。与父合金相比，在Fe站点时取代12.5％Mn（X = 0.25）会显着增加高温电阻率（\ r {HO}）和Seebeck系数的增强。但是，随着MN的浓度升高到0.25以上，注意到两个参数的大小都会降低。这些观察结果已被归因于（从理论分析）到使用MN替代的Fe2cral的带隙和电子结构的变化。由于缺乏质量波动和晶格菌株，因此在这一系列的Heusler合金中，导热率没有显着变化。另外，S将其幅度急剧改变，而跨界车从负面到900 K以上，这已归因于高温方向上电子在电子上的优势。在这一系列合金中，S和\ r {HO}表现出对Fe/Mn和Cr原子之间D-D杂交的载体浓度和强度的强烈依赖。
We investigate the high temperature thermoelectric properties of Heusler alloys Fe2-xMnxCrAl (0<x<1). Substitution of 12.5% Mn at Fe-site (x = 0.25) causes a significant increase in high temperature resistivity (\r{ho}) and an enhancement in the Seebeck coefficient (S), as compared to the parent alloy. However, as the concentration of Mn is increased above 0.25, a systematic decrement in the magnitude of both parameters is noted. These observations have been ascribed (from theoretical analysis) to a change in band gap and electronic structure of Fe2CrAl with Mn-substitution. Due to absence of mass fluctuations and lattice strain, no significant change in thermal conductivity is seen across this series of Heusler alloys. Additionally, S drastically changes its magnitude along with a crossover from negative to positive above 900 K, which has been ascribed to the dominance of holes over electrons in high temperature regime. In this series of alloys, S and \r{ho} shows a strong dependence on the carrier concentration and strength of d-d hybridization between Fe/Mn and Cr atoms.
