Coexistence of Giant Transverse Transport Properties and Complex Spin Configuration in Polycrystalline Kagomé Ferromagnet GdCo.

Kagomé lattice magnets have recently garnered significant interest due to the pronounced transverse transport characteristics, particularly in thermoelectric and spintronic applications, stemming from the interplay between topology and magnetism. Here, a comprehensive investigation of the magnetic, electrical, and thermoelectric transport properties, as well as the complex spin configurations, is conducted in a polycrystalline Kagomé ferromagnet GdCo. Strikingly, a giant anomalous Hall conductivity ≈2125 S cm is obtained at T = 10 K, which is primarily governed by the extrinsic skew-scattering mechanism. Simultaneously, a large anomalous Nernst effect, including both the Nernst coefficient ( ≈3.5 µV K at 250 K) and transverse thermoelectric conductivity ( ≈3.2 A m K at 210 K) are achieved, which surpass most of the typical Kagomé magnets. In addition, both appreciable topological Hall and Nernst effects imply the emergence of nontrivial spin structures in GdCo, correlating with the M-shaped MR(H) behavior. The remarkable observations of stable spontaneous Skyrmion bubbles and vortices in GdCo further substantiate the above conjecture. This study highlights the coexistence of multiple intriguing physical phenomena, making the Kagomé ferromagnet GdCo serve as a promising candidate for exploring transverse transport effects and the extremely rich underlying physics.