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

[8p-Z18-14] Anomalous Nernst effect under in- and out-of-plane heat flux in the Weyl ferromagnet Co₂MnGa thin films

〇(M2)Ryota Uesugi¹, Tomoya Higo^1,2, Zheng Zhu¹, Kouta Kondou^2,3, Akito Sakai^2,4, Mihiro Asakura⁴, Yoshichika Otani^1,2,3,5, Satoru Nakatsuji^1,2,4,5,6 (1.ISSP, Univ. of Tokyo, 2.JST CREST, 3.RIKEN CEMS, 4.Univ. of Tokyo, 5.Trans-Quantum Science Inst., Univ. of Tokyo, 6.Johns Hopkins Univ.)

Keywords:Nernst effect, Heusler alloy, Topological magnet

Anomalous Nernst effect (ANE) can generate an electromotive force perpendicular to the heat flux, which provide a technological potential for film-based thermoelectric devices. However, the conversion efficiency was thought that be limited to around 1 μV/K, which is hundred times smaller than the Seebeck coefficient obtained in conventional thermoelectric materials because it is depended on their own magnetization. Recently, we found that the non-collinear Weyl anti-ferromagnet Mn₃Sn and full-Heusler Weyl ferromagnet Co₂MnGa show the large ANE 0.35 and 6 μV/K respectively due to a large Berry curvature from Weyl points working as a fictitious magnetic field in the momentum space. We fabricated the Weyl ferromagnet Co₂MnGa thin films by DC magnetron sputtering and report ANE under in-plane and out-of-plane heat flux.