Abstract The demand of a full solid-state cooling technology based on magnetocaloric and thermoelectric effects has led to a growing interest in screening candidate materials with high-efficiency cooling performance, which also stimulates the exploration of magnetocaloric/thermoelectric hybrid cooling materials. A series of Gd/Bi0.5Sb1.5Te3 composites was fabricated in order to develop the hybrid cooling technology. The chemical composition, phase structure and diffusion kinetics across the reaction layers in Gd/Bi0.5Sb1.5Te3 composites were analyzed at different reaction temperatures. Micro-area elemental analysis indicates that the formation of interfacial phases is dominated by the diffusion of Gd and Te while the diffusion of Bi and Sb is impeded. The interfacial phases, including GdTe2, GdTe3, and intermediate phases GdTex, are identified by atomic-resolution electron microscopy. The concentration modulation of Gd and Te is adapted by altering the stacking of the Te square-net sheets and the corrugated GdTe sheets. Boltzmann-Matano analysis was applied to reveal the diffusion kinetics of Gd and Te in the interfacial layers. The diffusion coefficients of Te in GdTe2 and GdTe3 are much higher than that of Gd while in GdTe the situation is reversed. This study provides a clear picture to understand the interfacial phase structures down to an atomic scale as well as the interfacial diffusion kinetics in Gd/Bi0.5Sb1.5Te3 hybrid cooling materials.

中文翻译：

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Gd/Bi0.5Sb1.5Te3磁热/热电复合材料的原子分辨率界面结构和扩散动力学

摘要 基于磁热和热电效应的全固态冷却技术的需求导致对筛选具有高效冷却性能的候选材料越来越感兴趣，这也刺激了磁热/热电混合冷却材料的探索。为了开发混合冷却技术，制造了一系列 Gd/Bi0.5Sb1.5Te3 复合材料。在不同反应温度下分析了 Gd/Bi0.5Sb1.5Te3 复合材料中反应层的化学成分、相结构和扩散动力学。微区元素分析表明，界面相的形成以Gd和Te的扩散为主，而Bi和Sb的扩散受阻。界面相，包括 GdTe2、GdTe3 和中间相 GdTex，由原子分辨率电子显微镜识别。Gd 和 Te 的浓度调制通过改变 Te 方网片和波纹 GdTe 片的堆叠来调整。应用 Boltzmann-Matano 分析来揭示 Gd 和 Te 在界面层中的扩散动力学。Te在GdTe2和GdTe3中的扩散系数远高于Gd，而在GdTe中情况正好相反。该研究提供了清晰的图片，以了解低至原子尺度的界面相结构以及 Gd/Bi0.5Sb1.5Te3 混合冷却材料中的界面扩散动力学。应用 Boltzmann-Matano 分析来揭示 Gd 和 Te 在界面层中的扩散动力学。Te在GdTe2和GdTe3中的扩散系数远高于Gd，而在GdTe中情况正好相反。该研究提供了清晰的图片，以了解低至原子尺度的界面相结构以及 Gd/Bi0.5Sb1.5Te3 混合冷却材料中的界面扩散动力学。应用 Boltzmann-Matano 分析来揭示 Gd 和 Te 在界面层中的扩散动力学。Te在GdTe2和GdTe3中的扩散系数远高于Gd，而在GdTe中情况正好相反。该研究提供了清晰的图片，以了解低至原子尺度的界面相结构以及 Gd/Bi0.5Sb1.5Te3 混合冷却材料中的界面扩散动力学。