Breakthroughs in electrification, intelligent systems, and carbon-neutral technologies are driving an urgent demand for soft magnetic materials that simultaneously deliver high saturation magnetic flux density ( \({B}_{\text{s}}\) ), low coercivity ( \({H}_{\text{c}}\) ), large effective permeability ( \({\mu }_{\text{e}}\) ), and superior high-frequency stability. Fe-based amorphous and nanocrystalline alloys uniquely combine these attributes with excellent thermal stability and mechanical robustness, positioning them as prime candidates for next-generation energy systems. However, the composition–structure–property relationship remains only partially understood, and scalable strategies to translate laboratory performance into industrial deployment are still underdeveloped. To address these challenges, a unified framework integrating magnetic theory, microstructural design, and emerging computational methodologies is established. The roles of grain size, amorphous/nanocrystalline coupling, and alloying strategies in governing \({B}_{\text{s}}\) , \({H}_{\text{c}}\) , \({\mu }_{\text{e}}\) , and Curie temperature ( \({T}_{\text{c}}\) ) are elucidated by linking classical models (Herzer’s random anisotropy, Suzuki’s coupling) with density functional theory and machine learning driven predictions. Representative fabrication routes, including rapid solidification, magnetic-field annealing, spark plasma sintering, and additive manufacturing, are critically assessed in terms of both performance optimization and scalability. Notably, Fe-based nanocrystalline alloys such as FINEMET and NANOPERM achieve \({B}_{\text{s}}>1.5 \text{ T}\) , \({H}_{\text{c}}<10 \text{ A}/\text{m}\) , and core-loss reductions of 40%–70% relative to Si-steel, enabling high-efficiency transformers and power converters. A forward-looking roadmap is concluded for developing low-cost, high-performance Fe-based soft magnetic materials, bridging fundamental research and industrial application.
