The effects of the synergy of pressure regulation and Eu substitution on the microstructure and thermoelectric (TE) properties are investigated for type-I clathrates Eu[Formula: see text]Ba[Formula: see text]Cu6Si[Formula: see text]Ge[Formula: see text] ([Formula: see text], 0.5, 1, 1.5). The rare-earth-substituted and high-pressure modulated samples show complicated morphologies composed of abundant grains and rich in lattice defects. The Seebeck coefficient and the electrical conductivity of the rare-earth-substituted samples synthesized by HPHT method are consistent with [Formula: see text]-type conduction and metal-like behavior. The carrier concentration increases and the Hall carrier mobility decreases with increasing Eu substitution at room temperature. Although the increase of Eu filling rate decreased the Seebeck coefficient of the samples, it increased the power factor (PF) of the samples significantly. The thermal conductivity also reduced on account of Eu filling. As a result, a minimum [Formula: see text] value (0.67 Wm[Formula: see text]K[Formula: see text]) and a relatively higher zT value (0.68) are achieved. Compared to the Eu-free sample, the achieved zT value of the Eu-substituted sample is a [Formula: see text][Formula: see text]62% enhancement. So, high-pressure technique is an effective route to synthesize clathrate materials and optimize TE properties simultaneously.

中文翻译：

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压力调节和铕取代协同作用对I型包合物EuxBa8−xCu6Si16Ge24微观结构和热电性能的影响

研究了I型包合物Eu[公式：见正文]Ba[公式：见正文]Cu的压力调节和Eu取代的协同作用对微观结构和热电（TE）性能的影响6Si[公式：见正文]Ge[公式：见正文]（[公式：见正文], 0.5, 1, 1.5）。稀土取代和高压调制的样品表现出由丰富的晶粒和丰富的晶格缺陷组成的复杂形貌。HPHT法合成的稀土取代样品的塞贝克系数和电导率符合[公式：见正文]型导电和类金属行为。载流子浓度增加，霍尔载流子迁移率随着室温下 Eu 取代的增加而降低。Eu填充率的增加虽然降低了样品的塞贝克系数，但显着增加了样品的功率因数（PF）。由于Eu填充，热导率也降低了。因此，最小 [公式：见文本] 值 (0.67 Wm[公式：见文本]K[公式：见文本]）和相对较高的 zT 值（0.68）。与不含Eu的样品相比，Eu取代样品的zT值提高了[公式：见正文][公式：见正文]62%。因此，高压技术是合成笼形材料并同时优化热电性能的有效途径。