Abstract Topological Heusler ferromagnets have emerged as a promising material platform for realizing a large anomalous Nernst effect (ANE) due to their intrinsic Berry curvature. This work reports a significantly enhanced ANE in polycrystalline bulk Co 2 MnAl 1‐ x Si x , enabled by synergistic tuning of atomic ordering and Fermi level via Si substitution. A large anomalous Nernst thermopower of 4.9 µV K −1 and an anomalous Nernst conductivity of 1.46 A m −1 K −1 at 300 K are obtained in Co 2 MnAl 0.69 Si 0.31 . Furthermore, A centimeter‐sized bulk Nernst thermoelectric generator has been developed using Co 2 MnAl 0.69 Si 0.31 as the legs, which delivers an output voltage of 2.2 mV and a maximum power of 7.7 µW under a temperature difference of 15 K. These results highlight the potential of scalable, high‐performance polycrystalline topological magnets for transverse thermoelectric applications and pave the way for practical integration of ANE‐based devices.
Sheng et al. (2025) studied this question.