Nanoscale magnetic oxide interface enables high-magnetization and high-frequency amorphous soft magnetic composites

This is the authors' abstract. We don't add key points for this paper.

Amorphous soft magnetic composites (ASMCs) are essential for high-frequency electrical devices, yet their performance is constrained by the trade-off between saturation magnetization ( M s ) and high-frequency magnetic properties. Conventional ASMCs fabricated from micron-sized powder with non-magnetic insulating coatings typically suffer from undesirable M s and insufficient operating frequency owing to limited iron content, magnetic dilution, and large particle size, while complex processes further restrict precise performance regulation. Here, we introduce an approach that integrates in-situ nanoscale magnetic oxide engineering with ultra-low-pressure compaction to overcome these limitations. An ultrathin magnetic oxide layer (∼2 nm) is formed on nano-FeB amorphous powders via chemical reduction, enabling simultaneous electrical insulation and magnetic exchange coupling. The resulting powders exhibit a high M s of 172 emu g −1 owing to enhanced magnetic coupling across the magnetic oxide interfaces. The ASMCs consolidated at an ultra-low pressure (100 MPa), without additional coating or post-annealing, display stable permeability up to ∼85 MHz, a high quality factor of 105, and an expanded peak frequency of ∼80 MHz, benefiting from the strong demagnetizing field associated with abundant interparticle gaps. Meanwhile, the core loss below 100 kHz remains comparable to that of conventional micron-powder cores owing to nanoscale particle size and an insulating oxide layer. This work provides a new route for designing ASMCs for next-generation high-frequency magnetic components through in-situ magnetic oxide engineering.