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

10:30 AM - 10:45 AM JST(1:30 AM - 1:45 AM UTC)English Presentation

[20a-D61-6] Positive and negative anomalous Nernst coefficients in 2-dimensional layered MnAlGe thin films with large magnetic anisotropy

〇(P)Nanhe Kumar Gupta¹, Ryo TOYAMA¹, Benugopal BAIRAGYA¹, Keisuke MASUDA¹, Yuya SAKURABA¹ (1.Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science)

Keywords:

Anomalous Nernst Effect,Two- Dimenssional Layered Ferromagnet,Anomalous Hall Effect

Two -dimensional ferromagnets with remarkable transverse transport properties, low saturation magnetization, and high uniaxial magneto crystalline anisotropy constant are attracting attention for application in thermopower devices. MnAlGe is an emerging material class with various interesting properties owing to a layered topological nodal line. In this study, the anomalous Nernst effect in epitaxial MnAlGe film with a pseudo-two-dimensional structure consisting of Mn and Al-Ge layers was investigated over a wide temperature range (10-400 K). The relatively large anomalous Hall angles of ~0.032 (0.02) were obtained in the film at 25 (300) K, which could be attributed to layered topological nodal lines in these materials. The observed anomalous Nernst coefficient (S_ANE) of ~2.0 (-0.5) μV/K and anomalous Hall conductivity of 656 (138) S/cm yielded anomalous Nernst conductivity (ANC) of 4.5 (-0.17) A/(m K) at 25 (300) K, respectively. The sign change in S_ANE occurs at 125 K, which was not observed in the anomalous Hall effect of the film. We performed the first-principles calculation of ANC at 300K and found ANC shows a negative sign which agrees with the experimental observation.