Robust room-temperature anomalous Nernst effect over a broad thickness and composition range in chemically disordered FexPt100−x films

Abstract

The anomalous Nernst effect (ANE) has been under consideration for potential transverse thermoelectric applications. However, the utilized material systems are generally limited to chemically ordered crystals with notable features of nontrivial band topology and/or strong spin–orbit coupling, such as topological ferromagnets and antiferromagnets. In this study, we present the observation of a robust room-temperature ANE in a chemically disordered ferromagnet, specifically an A1-type FexPt100−x alloy. The observed anomalous Nernst thermopower Sxy (∼1.6 μV/K) remains stable over a wide range of thicknesses (6 ≤ t ≤ 100 nm) and compositions (46 ≤ x ≤ 67), which is in stark contrast to the common situation in topological ferromagnets. This behavior can be attributed to both the large anomalous Nernst conductivity αxy (∼1.3 A K−1 m−1), originating from Berry phase effects, as well as the significant Seebeck-driven anomalous Hall effect that modulates its action through mean-free-path and two-carrier models.