Thermoelectric M x Co4Sb12 skutterudites are well-known to exhibit a reduced thermal conductivity thanks to the rattling effect of the M-filler at the large cages occurring in the framework, centered at the 2a sites of the I m 3 ‾ $Im\overline{3}$ space group. A novel Eu-filled skutterudite has been synthesized under high-pressure conditions at 3.5 GPa in a piston-cylinder hydrostatic press. The structural refinement from high-angular resolution synchrotron X-ray diffraction (SXRD) patterns unveils an unusual position for Eu filler atoms. By difference Fourier synthesis they are found at 12d sites, conforming statistically occupied octahedra within the mentioned cages around 2a positions. The Debye temperature was estimated by averaging the isotropic displacements by the atomic masses, leading to θ D ${\theta }_{D}$ of 273(2) K. Oftedal plots concerning the y and z Sb fractional positions, the unit-cell parameter a and M filling fraction include the novel Eu specimen in the trend observed for other filled materials prepared under high-pressure, including rare-earths, alkali or alkali-earth elements, all accepted as rattlers in filled skutterudites. A total thermal conductivity (κ) of 0.82 W m−1 K−1 is measured at 773 K for Eu0.02(1)Co4Sb12, below that of other filled skutterudites, which is promoted by the enhanced phonon scattering of Eu located at 12d sites. FE-SEM images showed large, homogeneous grains, well compacted after the high-pressure synthesis.

中文翻译：

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高压条件下制备的填充 Eu x Co4Sb12 方钴矿中嘎嘎声原子的新晶体位置

热电M X 有限公司4个锑12众所周知，由于 M 填料在框架中以 2 为中心的大笼中的嘎嘎声效应，方钴矿会表现出较低的热导率一种网站的 我 米 3个 ‾ $Im\overline{3}$ 空间群。在 3.5 GPa 的高压条件下，在活塞缸静压机中合成了一种新型的充满 Eu 的方钴矿。高角分辨率同步加速器 X 射线衍射 (SXRD) 图案的结构改进揭示了 Eu 填充原子的不寻常位置。通过差分傅立叶综合，他们发现在 12d地点，符合统计上提到的笼子内占据的八面体大约 2一种职位。德拜温度是通过平均原子质量的各向同性位移来估计的，导致 θ 丁 ${\theta}_{D}$ 273(2) K. Oftedal 图关于是和zSb 小数位置，晶胞参数一种和 M 填充分数包括在高压下制备的其他填充材料观察到的趋势中的新型 Eu 样本，包括稀土、碱金属或碱土元素，所有这些都被认为是填充方钴矿中的响尾蛇。总热导率（κ) 的 0.82 W·m−1钾−1Eu 的测量值为 773 K0.02(1)有限公司4个锑12，低于其他填充的方钴矿，这是由位于 12 的 Eu 增强的声子散射促进的d网站。FE-SEM 图像显示大而均匀的晶粒，在高压合成后压实良好。