[20a-D61-1~9] 10.1 Emerging materials in spintronics and magnetics (including fabrication and characterization methodologies)

11:15 AM - 11:30 AM JST(2:15 AM - 2:30 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[20a-D61-9] Observation of the giant anomalous Nernst effect in the Weyl ferromagnet Co₂MnGa polycrystalline films

〇(P)Ryota Uesugi^1,2, Tomoya Higo^1,2,3, Satoru Nakatsuji^1,2,3,4,5 (1.Dep. of Phys., Univ. of Tokyo, 2.ISSP, Univ. of Tokyo, 3.CREST, JST, 4.TSQS, Univ. of Tokyo, 5.IQM, JHU)

Keywords:

anomalous Nernst effect,Weyl ferromagnet,topological band structure

Recently, magnetic Weyl materials such as Mn₃Sn and Co₂MnGa showing large anomalous Nernst effects (ANE) have attracted attention due to the enhancement of transverse transport properties by the Berry curvature. On the other hand, polycrystalline films should be fabricated on amorphous templates for the application of thermoelectric devices such as heat flux sensors using ANE. Transport properties derived from the topological band structure are resilient to disorder and impurities in the required crystal structure, and even polycrystalline samples may exhibit a large transverse response if the quality of each crystallite is sufficiently high. However, only a small anomalous Nernst effect had been obtained in films deposited directly on the amorphous template. In this study, we report the largest ANE of −5.4 μV/K in Co₂MnGa films on the amorphous template directly by successfully fabricating polycrystalline film with high-quality crystal grains using a sputtering method.