Nonlinear Transverse Transport in a Ferromagnetic Polar Metal

Symmetry‐driven nonlinear responses in quantum materials hold key importance to uncover emergent electronic phenomena. While the nonlinear transport has been extensively studied in nonmagnetic materials, its correlation with ferromagnetism remains an open and intriguing question. Here, we explore the nonlinear transverse transport in a ferromagnetic polar metal. Specifically, in non‐centrosymmetric SrRuO 3 (111) thin films, we observed an abrupt enhancement of the time‐reversal‐even transverse nonlinear signal during the paramagnetic‐ferromagnetic transition. Scaling analysis reveals a sign reversal of both the skew scattering and side jump contributions upon the emergence of ferromagnetism. Combined with theoretical analysis, we correlate this behavior with a sign change of Berry curvature triple on the Fermi surface, driven by the redistribution of Berry curvature hot spots across the magnetic transition. Our findings unveil that magnetic ordering can induce a dramatic nonperturbative change of nonlinear responses, establishing correlated magnetic oxides as a promising platform for exploring tunable magnetic nonlinear transport effects.