The 81st JSAP Autumn Meeting, 2020

Presentation information

Oral presentation

9 Applied Materials Science » 9.4 Thermoelectric conversion

[8p-Z18-1~16] 9.4 Thermoelectric conversion

Tue. Sep 8, 2020 12:30 PM - 5:15 PM Z18

Mikio Koyano(JAIST), Takahiro Tomita(東大), Takafumi Ishibe(Osaka Univ.)

4:15 PM - 4:30 PM

[8p-Z18-13] Topologically enhanced anomalous Nernst effect in Fe3Ga1-xAlx and Fe3Al1-xSix

〇(M2)Yangming Wang1, Zili Feng1, Taishi Chen1,2, Akito Sakai1,2,3, Satoru Nakatsuji1,2,3,4 (1.ISSP, UTokyo, 2.CREST, 3.Dep.Phys, UTokyo, 4.Dep.Phys, JHU)

Keywords:Anomalous Nernst effect, Iron-based alloy, topological energy band

Anomalous Nernst effect (ANE) is the generation of a transverse voltage perpendicular to both the magnetization and the heat current in ferromagnets, which gains increasing interest due to its various potential benefits[1]. Recently, iron-based binary alloy Fe3Ga and Fe3Al were discovered with record-large anomalous Nernst value[2]. This system will provide an excellent research platform to explore the topological origin of such a large ANE.
We have systematically synthesized polycrystalline Fe3Ga1-xAlx and Fe3Al1-xSix with different doping levels (x=0, 0.25, 0.5, 0.75, 1) and studied the dependence of the magnetic and transport properties, specially anomalous Hall and Nernst effect on chemical doping. We found the giant Nernst signal remains sizable even in polycrystalline samples, which declares that arc-melting polycrystals can also provide essential information in material screening procedures. Moreover, a systematic and nearly linear change of the ANE was observed as a function of chemical doping, indicating the intrinsic contribution to the ANE is dominant and is robust against chemical disorder, which is a defining characteristic of topological states.
[1] Mizuguchi, M,et al. Science and technology of advanced materials, 2019, 20 (1): 262-275.
[2] Sakai, A, et al. Nature, 2020, 581: 53–57