| Jul 21, 2025 |
Magnetic nanofilm blocks 5G signals and resists corrosion in harsh environments
Researchers develop a flexible magnetic nanofilm that shields 5G signals and withstands corrosion, offering a new solution for electronics and marine applications.
(Nanowerk News) Modern electronics has brought with it a growing concern: electromagnetic wave pollution. As wireless devices and networks proliferate, especially in the age of 5G, the need for effective shielding materials has become increasingly urgent. To address this, researchers are developing new electromagnetic wave-absorbing materials that are both efficient and adaptable to harsh environments.
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One promising direction involves combining materials with different magnetic properties—specifically, pairing soft and hard magnetic materials to form what are known as heterostructures. These combinations can create magnetic exchange coupling at their interfaces, a phenomenon that significantly enhances microwave absorption. However, past efforts have struggled with poor interfacial contact and impedance mismatches, limiting their effectiveness.
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To overcome these challenges, a team led by Professor Dong Wang at the School of Materials Science and Engineering, Shandong University of Technology, has engineered a refined heterostructure featuring zinc ferrite (ZnFe₂O₄), iron carbide (Fe₃C), and carbon nanosheets.
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Their work, published in Nano Research ("Tailored hard/soft magnetic heterostructure anchored on 2D carbon nanosheet for efficient microwave absorption and anti-corrosion property"), presents a nanocomposite called Fe₃C/ZnFe₂O₄/C (abbreviated as FZC), which exhibits superior electromagnetic absorption and corrosion resistance.
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Using a specialized in-situ blowing gel process, the team anchored soft magnetic ZnFe₂O₄ nanoparticles and hard magnetic Fe₃C particles onto two-dimensional carbon sheets. This approach created a dense network of heterointerfaces, boosting magnetic exchange interactions and enhancing electromagnetic wave attenuation through polarization loss. At the same time, the 2D carbon structure improved impedance matching and contributed to dielectric loss, making the material more effective overall.
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The performance results are striking. The FZC-1 variant demonstrated a wide effective absorption bandwidth (EAB) of 4.56 GHz and a minimum reflection loss (RLmin) of -65.6 dB, indicating strong absorption of electromagnetic waves. Radar cross-section (RCS) simulations confirmed its potential use in stealth applications. Additionally, density functional theory (DFT) calculations supported the presence of dynamic charge redistribution at the interface—an indicator of robust magnetic coupling.
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Beyond absorption, the material also shows strong promise in anti-corrosion applications. By stacking layers of FZC-1 with reduced graphene oxide (rGO), the team fabricated a flexible composite film capable of shielding 5G signals. The stacked 2D morphology forms a complex structure that limits the penetration of corrosive saline ions, a so-called “maze effect,” which enhances the material’s durability in marine environments.
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According to Professor Wang, these advances in controlling nanoscale heterostructures open new avenues for interface engineering, with applications spanning electromagnetic shielding, corrosion-resistant coatings, and stealth technology.
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