Giant and Robust Anomalous Nernst Effect in a Polycrystalline Topological Ferromagnet at Room Temperature
Giant and Robust Anomalous Nernst Effect in a Polycrystalline Topological Ferromagnet at Room Temperature
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室温下多晶拓扑铁磁体中巨大而鲁棒的反常能斯特效应
DOI：
10.1002/adfm.202206519
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发表时间：
2022
影响因子：
19
通讯作者：
Nakatsuji Satoru
中科院分区：
文献类型：
--
作者：
Feng Zili;Minami Susumu;Akamatsu Shuhei;Sakai Akito;Chen Taishi;Nishio‐Hamane Daisuke;Nakatsuji Satoru
拓扑磁体的最新发现为利用反常能斯特效应（ANE）开发更简单的热电转换模块开辟了一条新途径。为了加速这种创新，设计适合工业过程的材料至关重要，因此高度期望高ANE多晶材料。最近，在拓扑铁磁体Fe 3Ga的单晶中已经报道了巨大的室温ANE。由于它的立方结构，反常霍尔效应和ANE是各向同性的。这些性质潜在地允许采用多晶形式的材料来设计基于ANE的热电堆。在这里，报道了多晶FexGa 4 −x（2.96 <x< 3.15）中的巨大而坚固的室温ANE，其可以增强到5.4 µV K−1;这个值达到了多晶磁体的最高室温记录。实验结果与理论研究的Fe掺杂对FexGa 4 − x输运性质的影响的比较表明，拓扑节点网络结构附近的费米能量调谐是增强ANE的关键。此外，在扩展的组成区域观察到大于5.1 µV K− 1的大值，证实了拓扑电子结构的鲁棒特性。
Recent discoveries of the topological magnets have opened a new path for developing a much simpler thermoelectric conversion module using the anomalous Nernst effect (ANE). To accelerate such innovation, it is essential to design materials suitable for industrial processes, and thus a high‐ANE polycrystalline material has been highly desired. Recently, the giant room‐temperature ANE has been reported in single crystals of the topological ferromagnet Fe3Ga. Owning to its cubic structure, the anomalous Hall effect and ANE are isotropic. These properties potentially allow to employ a polycrystalline form of the material to design an ANE‐based thermopile. Here, a giant and robust room‐temperature ANE in the polycrystalline FexGa4−x(2.96 <x< 3.15) is reported, which can be enhanced up to 5.4 µV K−1; this value hits the highest room‐temperature record for polycrystalline magnets. Comparison of the experimental results with the theoretical study of the Fe‐doping effect on the transport properties of FexGa4−xreveals that the Fermi energy tuning near the topological nodal‐web structure is the key to enhancing the ANE. Moreover, the large value of more than 5.1 µV K−1is observed for an extended region of composition, confirming the robust characteristics of the topological electronic structure.