Local structure and atomic dynamics in Fe2VAl Heusler-type thermoelectric material: The effect of heavy element doping
Local structure and atomic dynamics in Fe2VAl Heusler-type thermoelectric material: The effect of heavy element doping
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DOI：
10.1103/physrevb.101.024302
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发表时间：
2020-01
影响因子：
3.7
通讯作者：
K. Kimura;K. Yamamoto;K. Hayashi;Satoshi Tsutsui;N. Happo;S. Yamazoe;H. Miyazaki;S. Nakagami;J. Stellhorn;S. Hosokawa;T. Matsushita;H. Tajiri;A. Ang;Y. Nishino
中科院分区：
文献类型：
--
作者：
K. Kimura;K. Yamamoto;K. Hayashi;Satoshi Tsutsui;N. Happo;S. Yamazoe;H. Miyazaki;S. Nakagami;J. Stellhorn;S. Hosokawa;T. Matsushita;H. Tajiri;A. Ang;Y. Nishino
用X射线吸收精细结构、X射线荧光全息术和非弹性X射线散射技术研究了Ta掺杂对${\mathrm{Fe}}_{2}({\mathrm{V}}_{0.95}{\mathrm{Ta}}_{0.05}$)Al-Heusler型热电材料的局域结构和原子动力学的影响。XAFS和XFH结果表明，Ta和周围的Fe原子之间的位置关联比V和Fe之间的位置关联要严格得多。在IXS结果中，我们观察到未掺杂的{{Fe}}{2}\{Val}的声学声子在能量范围内有一个宽的无色散模，这就是所谓的共振模。这些结果揭示了重掺杂的动力学特征明显不同于基质元素的动力学特征，它干扰了声子的相干性，应该有助于提高隔热性能。
X-ray absorption fine structure (XAFS), x-ray fluorescence holography (XFH), and inelastic x-ray scattering (IXS) techniques were applied to an ${\mathrm{Fe}}_{2}({\mathrm{V}}_{0.95}{\mathrm{Ta}}_{0.05}$)Al Heusler-type thermoelectric material to investigate the doping effect of Ta on the local structure and the atomic dynamics. The XAFS and XFH results show that the positional correlation between Ta and surrounding Fe atoms is much more rigid than that between V and Fe. In the IXS results, we observed a broad dispersionless mode in the energy range of the acoustic phonons of undoped ${\mathrm{Fe}}_{2}\mathrm{VAl}$, which is regarded as the so-called resonant mode. These results revealed a clearly different feature of the dynamics of heavy dopants from that of the matrix element, which disturbs the coherency of phonons and should contribute to the enhancement of the thermal insulation.