Programmed Domain Architectures Enable Ultra‐Low Magnetic Loss in Amorphous Soft Magnets

Advanced soft magnetic materials with low energy dissipation are essential for efficient power conversion in an increasingly electrified world. The Fe-based amorphous ribbons are promising candidates owing to their intrinsically low coercivity and high permeability. However, substantial excess loss arising from the inevitable magnetic domain dynamics remains a fundamental barrier to further reducing the energy dissipation. Here, we establish a domain-engineering strategy that approaches the fundamental limit imposed by eddy-current dissipation, which is realized by deterministically programming stress-induced magnetic anisotropy and the resulting domain architecture. In particular, we show that the programmed domain architecture from laser irradiation could reshape magnetization dynamics, resulting in a 72.3% reduction in total loss and a record low value of 30.5 ± 0.6 mW/kg at 50 Hz and 1.3 T. By integrating uniaxial tensile experiments and multiscale simulations, we uncover a direct stress-anisotropy-domain-loss scaling behavior, providing mechanistic clarity into how laser-induced stress governs magnetic dissipation in amorphous magnets. These findings position domain architecture as a mesoscopic parameter for deterministically reducing the dynamic magnetic losses in amorphous magnets. Our results could potentially accelerate the development of transformative energy conversion technologies that are vital for promoting an electrified and sustainable society.