Sequential Architecture Induced Strange Dielectric‐Magnetic Behaviors in Ferromagnetic Microwave Absorber

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(27)

Published: March 27, 2023

Abstract The high filler loading (FL) is a bottleneck in developing lightweight ferromagnetic microwave absorbers (MAs) for the actual applications. Sequential architecture design of MAs can induce strange physical behaviors due to unique coupling‐enhancement effect between functional units, providing vast potential achieving absorption performance. However, FLs current sequential fail be designed on demand because dielectric‐magnetic cannot fulfilled. influence engineering macroscopic properties or microscopic loss mechanism still needs more exploration. Herein, based four mesoscopic models (particles, chains, bundles, and fibers) series with different architectures are prepared via bottom‐up self‐assembly method. fibrous samples exhibit best performance (−51.3 dB, 4.12 GHz) at breakthrough FL 2 wt%, which one order magnitude less than other MAs. Strange behaviors, including negative permittivity heterodromous chiral vortex, occur units lateral configurations. Further, special established reveal attenuation evolutionary mechanism. This study clarifies relationship provides new sight understand electromagnetic

Language: Английский

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Porifera‐Inspired Lightweight, Thin, Wrinkle‐Resistance, and Multifunctional MXene Foam

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(14)

Published: Dec. 26, 2023

Abstract Transition metal carbides/nitrides (MXenes) demonstrate a massive potential in constructing lightweight, multifunctional wearable electromagnetic interference (EMI) shields for application various fields. Nevertheless, it remains challenging to develop facile, scalable approach prepare the MXene‐based macrostructures characterized by low density, thickness, high mechanical flexibility, and EMI SE at same time. Herein, ultrathin MXene/reduced graphene oxide (rGO)/Ag foams with porifera‐inspired hierarchically porous microstructure are prepared combining Zn 2+ diffusion induction hard template methods. The hierarchical porosity, which includes mesoporous skeleton microporous MXene network within skeleton, not only exerts regulatory effect on stress distribution during compression, making rubber‐like resistant wrinkling but also provides more channels multiple reflections of waves. Due interaction between Ag nanosheets, MXene/rGO, structure, is possible produce an outstanding shielding performance specific surface effectiveness reaching 109152.4 dB cm 2 g −1 . Furthermore, exhibit multifunctionalities, such as transverse Joule heating, longitudinal heat insulation, self‐cleaning, fire resistance, motion detection. These discoveries open up novel pathway development lightweight materials considerable anti‐interference devices.

Language: Английский

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Interface-induced dual-pinning mechanism enhances low-frequency electromagnetic wave loss

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 17, 2024

Abstract Improving the absorption of electromagnetic waves at low-frequency bands (2-8 GHz) is crucial for increasing (EM) pollution brought about by innovation fifth generation (5G) communication technology. However, poor impedance matching and intrinsic attenuation material in hinders development wave absorbing (EMWA) materials. Here we propose an interface-induced dual-pinning mechanism establish a magnetoelectric bias interface constructing bilayer core-shell structures NiFe 2 O 4 (NFO)@BiFeO 3 (BFO)@polypyrrole (PPy). Such heterogeneous could induce distinct magnetic pinning moment ferromagnetic NFO dielectric dipole rotation PPy. The establishment effect resulted optimized enhanced bands, leading to better EMWA performance. minimum reflection loss (RL min ) thickness 4.43 mm reaches -65.30 dB (the optimal efficiency 99.99997%), effective bandwidth (EAB) can almost cover C-band (4.72 ~ 7.04 with low filling 15.0 wt.%. This work proposes optimize (EMW) pave avenue research high-performance absorbers.

Language: Английский

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Hierarchical Fe-Co@TiO₂ with Incoherent Heterointerfaces and Gradient Magnetic Domains for Electromagnetic Wave Absorption

ACS Nano, Journal Year: 2023, Volume and Issue: 18(1), P. 560 - 570

Published: Dec. 18, 2023

Induced polarization response and integrated magnetic resonance show prosperous advantages in boosting electromagnetic wave absorption but still face huge challenges revealing the intrinsic mechanism. In this work, we propose a self-confined strategy to construct hierarchical Fe-Co@TiO2 microrods with numerous incoherent heterointerfaces gradient domains. The results demonstrate that use of polyvinylpyrrolidone (PVP) coating is crucial for subsequent deposition Co-zeolitic imidazolate frameworks (ZIF-67), distance ordered arranged metal ions manipulates size domains, pyrolysis PVP layers restricts eutectic process Fe-Co alloys some extent. As result, these introduced lattice defects, oxygen vacancies, inevitably generate strong response, regulated domains realize resonance, including macroscopic coupling, long-range diffraction, nanoscale bridge connection, both mechanisms dissipating energy are quantitatively clarified by Lorentz off-axis electron holography. Owing cooperative merits, absorbents exhibit enhanced intensity bandwidth. This study inspires us develop generalized manipulating theory provides versatile methodology clarifying loss

Language: Английский

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Electrospinning fabrication and ultra-wideband electromagnetic wave absorption properties of CeO2/N-doped carbon nanofibers

Nano Research, Journal Year: 2022, Volume and Issue: 15(9), P. 7788 - 7796

Published: July 14, 2022

Language: Английский

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