This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers at South China University of Technology, in collaboration with the Dongguan Institute of Materials Science and Technology, Chinese Academy of Sciences, have developed a novel supranano multi-precipitate microstructure in amorphous soft magnetic composites using Ar/O₂ plasma treatment. By facilitating magnetic-moment reversal, this approach significantly reduced coercivity while maintaining excellent overall performance.
The optimized material exhibits an ultralow coercivity of 0.13 Oe, an effective permeability of 37.3, a high saturation magnetization of 185 emu g-1 and an ultralow core loss of 191.18 kW m⁻³ at 1 MHz and 20 mT. These results provide a promising strategy for developing next-generation soft magnetic composites for miniaturized, high-frequency and high-efficiency power electronics devices. The study was recently published in Materials Futures.
Soft magnetic composites (SMCs) have attracted considerable interest for high-frequency power electronics devices because of their favorable magnetic properties. Fe-based amorphous alloys are particularly promising owing to their intrinsically low coercivity and core loss. However, achieving a simultaneous balance among saturation magnetization, effective permeability and core loss remains challenging.
The limited deformability of amorphous powders creates internal air gaps during compaction, weakening interparticle magnetic coupling and reducing effective permeability. Increasing the compaction pressure can improve density but also introduces internal stresses and magnetic-domain pinning sites, thereby increasing coercivity and hysteresis loss. Although conventional nanocrystallization can improve magnetic performance by controlling nanocrystal size and distribution, simultaneously optimizing these competing properties remains difficult.
A simple microstructural strategy capable of combining high permeability and saturation magnetization with low coercivity and core loss is therefore highly desirable. The researchers developed a novel supranano multi-precipitate microstructure in amorphous soft magnetic composites using Ar/O2 plasma treatment followed by conventional cold compaction. The results indicate that the high-energy plasma induces the formation of ultrafine α-Fe, Fe3O4, SiO2 and Fe2O3 precipitates with sizes of only 0.8–2.5 nm, which are dispersed in the surface layer of amorphous powders.
These supranano precipitates act as preferential nucleation sites for magnetic-moment reversal, facilitating magnetization reversal and substantially reducing coercivity. As a result, the optimized SMC achieves an ultralow coercivity of 0.13 Oe and, consequently, a high effective permeability of 37.3, a high saturation magnetization of 185 emu g-1 and an ultralow core loss of 191.18 kW m-3 at 1 MHz and 20 mT. These results highlight the potential of supranano multi-precipitate engineering for balancing magnetic properties in amorphous SMCs.
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