The miniaturization and integration of electronic devices have driven an increasing demand for high-frequency soft magnetic materials. Traditional soft magnetic ferrites, while exhibiting good frequency stability, suffer from low saturation magnetization and poor temperature stability, making them unsuitable for integrated circuits. Developing soft magnetic materials with both high-frequency stability and high saturation magnetization has become a critical challenge.
Methods
This study employed a cold sintering technique to fabricate a soft magnetic composite featuring a magnetic vortex structure. Ultrafine FeSiAl particles were magnetically isolated and covalently bonded by an Al₂SiO₅/SiO₂/Fe₂(MoO₄)₃ multilayered heterostructure. To investigate the microstructure and magnetic domain structure of the composite, various characterization techniques were employed, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Lorentz transmission electron microscopy (L-TEM).
Ultra-high frequency stability: The composite material exhibits a permeability of 13, which remains stable up to 1 GHz. High saturation magnetization: The composite material achieves a high saturation magnetization of 105 Am²/kg. High mechanical strength: The composite material demonstrates an ultimate compressive strength of 337.1 MPa.
Revealing magnetic vortex characteristics: This study deepens our understanding of the high-frequency characteristics of magnetic vortex structures.
Designing novel magnetic devices: This research provides a new approach for designing novel integrated magnetic devices.
Promising applications: The composite material holds great potential for applications in high-frequency inductors, radio frequency oscillators, and spintronic devices.
Fig. 1. Domain structure and static magnetic properties of FeSiAl particles. The Al₂SiO₅/SiO₂/Fe₂(MoO₄)₃ multilayered heterostructure acts as a magnetic isolation layer, effectively reducing the coercivity of the composite. The magnetically isolated vortex structure promotes magnetization rotation, contributing to the high-frequency stability of the composite.
G. Bai, J. Sun, Z. Zhang, X. Liu, S. Bandaru, W. Liu, Z. Li, H. Li, N. Wang, X. Zhang, Vortex-based soft magnetic composite with ultrastable permeability up to gigahertz frequencies, Nature Communications 15(1) (2024) 2238. https://doi.org/10.1038/s41467-024-46650-9
