The ability to control chemical and physical structuring at the nanometre scale is important for developing high-performance thermoelectric materials. Progress in this area has been achieved mainly by enhancing phonon scattering and consequently decreasing the thermal conductivity of the lattice through the design of either interface structures at nanometre or mesoscopic length scales or multiscale hierarchical architectures. A nanostructuring approach that enables electron transport as well as phonon transport to be manipulated could potentially lead to further enhancements in thermoelectric performance. Here we show that by embedding nanoparticles of a soft magnetic material in a thermoelectric matrix we achieve dual control of phonon- and electron-transport properties. The properties of the nanoparticles—in particular, their superparamagnetic behaviour (in which the nanoparticles can be magnetized similarly to a paramagnet under an external magnetic field)—lead to three kinds of thermoelectromagnetic effect: charge transfer from the magnetic inclusions to the matrix; multiple scattering of electrons by superparamagnetic fluctuations; and enhanced phonon scattering as a result of both the magnetic fluctuations and the nanostructures themselves. We show that together these effects can effectively manipulate electron and phonon transport at nanometre and mesoscopic length scales and thereby improve the thermoelectric performance of the resulting nanocomposites.

中文翻译：

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热电性能的超顺磁性增强

在纳米尺度上控制化学和物理结构的能力对于开发高性能热电材料非常重要。该领域的进展主要是通过增强声子散射并因此通过设计纳米或介观长度尺度的界面结构或多尺度分层结构来降低晶格的热导率来实现的。一种能够操纵电子传输和声子传输的纳米结构方法可能会进一步提高热电性能。在这里，我们展示了通过在热电基质中嵌入软磁材料的纳米粒子，我们实现了声子和电子传输特性的双重控制。纳米粒子的特性——尤其是，它们的超顺磁性行为（其中纳米粒子在外部磁场下可以像顺磁体一样被磁化）——导致三种热电磁效应：电荷从磁性夹杂物转移到基体；超顺磁涨落引起的电子多重散射；由于磁涨落和纳米结构本身导致声子散射增强。我们表明，这些效应可以有效地在纳米和介观长度尺度上操纵电子和声子传输，从而提高所得纳米复合材料的热电性能。电荷从磁性夹杂物转移到基体；超顺磁涨落引起的电子多重散射；由于磁涨落和纳米结构本身导致声子散射增强。我们表明，这些效应可以有效地在纳米和介观长度尺度上操纵电子和声子传输，从而提高所得纳米复合材料的热电性能。电荷从磁性夹杂物转移到基体；超顺磁涨落引起的电子多重散射；由于磁涨落和纳米结构本身导致声子散射增强。我们表明，这些效应可以有效地在纳米和介观长度尺度上操纵电子和声子传输，从而提高所得纳米复合材料的热电性能。