Supranano multi-precipitate balances comprehensive properties in amorphous soft magnetic composites

Generally, it is difficult to balance the comprehensive properties of saturation magnetization, effective permeability, and core loss in soft magnetic composites (SMCs), aiming to address the challenges of miniaturization, high-frequency, and high efficiency. Herein, we report a novel supranano multi-precipitate microstructure in amorphous SMCs via conventional cold compaction, which is located inside a nanosized surface layer of amorphous powders and was modulated by Ar and O₂ plasma treatment. The multi-precipitate contains 0.8 nm α-Fe, 1.6 nm Fe₃O₄, and 2.5 nm SiO₂ and Fe₂O₃, which are dispersedly distributed in the amorphous matrix. The SMCs showcase a coercivity of 0.13 Oe, achieving the minimum for typical amorphous and nanocrystalline SMCs so far, and consequently the balanced properties of high effective permeability of 37.3, and ultralow core loss of 191.18 kW m^-3 at 1 MHz and 20 mT. This work paves the way for the development of next-generation SMCs via conventional cold compaction.