Magnetic Properties of Soft Magnetic Composites

Soft magnetic composites (SMCs) are engineered materials in which ferromagnetic powder particles are insulated and compacted to produce cores that combine high magnetic permeability with minimal electrical losses. Their performance is determined by intrinsic properties—saturation magnetisation, permeability and coercivity—as well as extrinsic factors such as particle size, insulation layer, porosity and heat treatment. Advances in amorphous and nanocrystalline powders have enabled remarkable reductions in core loss at high frequencies, while novel coatings and hybrid powder mixtures improve interparticle coupling and mechanical integrity. By tailoring microstructure—whether through critical‐state ordering in amorphous matrices or selective incorporation of high‐magnetisation fillers—researchers achieve a balance between high saturation magnetisation, low hysteresis loss and suppressed eddy currents. SMCs underpin the miniaturisation of inductors, transformers and electric‐machine components for renewable energy systems and electric vehicles, offering three‐dimensional shaping capabilities and design freedom beyond laminated steels.

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Magnetic Properties of Soft Magnetic Composites publication trend

The graph below shows the total number of articles in magnetic properties of soft magnetic composites across all publications each year (not limited to Nature Index journals).

Technical terms

Soft magnetic composite (SMC): A bulk magnetic core formed by electrically insulated ferromagnetic powders compacted into complex shapes to achieve high permeability and low eddy current losses.

Permeability (µ): A measure of a material’s ability to support the formation of a magnetic field within itself, determining inductance and magnetic flux density at a given magnetising force.

Saturation magnetisation (Ms): The maximum magnetisation a material can attain under an external magnetic field when all magnetic domains are aligned.

Core loss: The total energy loss in a magnetic core under alternating magnetisation, comprising hysteresis loss, eddy current loss and anomalous loss components, typically measured in mW cm⁻³.

Eddy current loss: Heat generated by circulating currents induced in conductive regions of the core during rapid magnetic field changes, which increases with frequency and material conductivity.

References

1. Critical state-induced emergence of superior magnetic performances in an iron-based amorphous soft magnetic composite. Materials Futures (2024).
2. Fe-Based Amorphous Magnetic Powder Cores with Low Core Loss Fabricated by Novel Gas–Water Combined Atomization Powders. Materials (2022).
3. Enhanced Permeability of Fe-Based Amorphous Powder Cores Realized through Selective Incorporation of Carbonyl Iron Powders at Inter-Particle Voids. Metals (2021).