Mechanism of strong enhancement of anomalous Nernst effect in Fe by Ga substitution
Mechanism of strong enhancement of anomalous Nernst effect in Fe by Ga substitution
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DOI：
10.1103/physrevmaterials.3.114412
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发表时间：
2019-11-25
影响因子：
3.4
通讯作者：
Sakuraba, Yuya
中科院分区：
文献类型：
--
作者：
Nakayama, Hiroyasu;Masuda, Keisuke;Sakuraba, Yuya
我们研究了沉积在 MgO(001) 单晶基底上的具有不同 Ga 原子组成 (x = 0-0.44) 的 Fe1-xGax 合金薄膜的反常能斯特效应 (ANE)。我们发现，尽管饱和磁化强度随着 x 的增加而降低，但 ANE 的大小随着 x 的增加而增加，直至 x = 0.32，这表明内在机制对观察到的 ANE 的主要贡献。 bcc Fe0.68Ga0.32 薄膜的 ANE 大小达到 2.4 μV/K，比纯 Fe 薄膜高两个数量级。磁输运测量和第一性原理计算表明，bcc Fe1-xGax 中较大的 ANE 是由较大的横向 Peltier 系数引起的。横向珀耳帖系数随着 x 的增加而急剧增强，可归因于通过电子掺杂效应进行的小费米能级调谐。因此，我们预计我们的发现将为通过 ANE 增强热电提供重要的信息。
We have investigated the anomalous Nernst effect (ANE) in Fe1-xGax alloy films with different Ga atomic compositions (x = 0-0.44) deposited on MgO(001) single-crystalline substrates. We found that the magnitude of the ANE increases with increasing x up to x = 0.32 even though the saturation magnetization decreases with increasing x, suggesting a dominant contribution of the intrinsic mechanism on the observed ANE. The magnitude of the ANE reaches 2.4 mu V/K in bcc Fe0.68Ga0.32 film, which is two orders of magnitude greater than that of pure Fe film. The magnetotransport measurements and the first-principles calculations revealed that the large ANE in bcc Fe1-xGax is caused by the large transverse Peltier coefficient. The drastic enhancement of the transverse Peltier coefficient with increasing x can be attributed to small Fermi level tuning through the electron doping effect. Thus, we anticipate that our finding will provide a crucial piece of information to enhance the thermopower through the ANE.