Large anomalous Nernst effects at room temperature in Fe 3 Pt thin films.

Heat current in ferromagnets can generate a transverse electric voltage perpendicular to magnetization, which is known as anomalous Nernst effect (ANE). ANE originates intrinsically from the combination of large Berry curvature and density of states near the Fermi energy E F . It shows technical advantages over conventional longitudinal Seebeck effect in converting waste heat to electricity due to its unique transverse geometry. However, materials showing giant ANE especially at zero magnetic field, remain to be explored. Herein, we report the discovery of a large ANE thermopower of S yx ≈ 2 µV K -1 at room temperature in ferromagnetic Fe 3 Pt epitaxial films, which also shows a giant transverse thermoelectric conductivity of α yx ≈ 4 A K -1 m -1 and a remarkable coercive field of about 1300 Oe. Besides the consequent strong magnetic anisotropy, our theoretical analysis reveals that the strong spin-orbit interaction in addition to the hybridization between Pt 5d and Fe 3d electrons leads to a series of distinct energy gaps and large Berry curvature in the Brillouin zone, which is the key for the large ANE. These results highlight the important roles of both Berry curvature and spin-orbit coupling in achieving large ANE at zero magnetic field, providing pathways to explore materials with giant transverse thermoelectric effect without external magnetic field. This article is protected by copyright. All rights reserved.