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This work reports, microwave characterization of nanocrystalline nickel-polyvinylidene fluoride (n-Ni/PVDF) composites with an aim to explore their electromagnetic interference (EMI) shielding and absorption properties. The composites were fabricated using compression hot molding process at an optimum level of temperature and pressure. The electrical properties of the samples are computed using the measured scattering parameters in the X-band. The wave absorption capability of a single layer absorbing structure is theoretically evaluated by employing the computed electrical parameters. Besides, the shielding effectiveness (SE) of free standing samples are also calculated using transmission line model and compared with the experimentally obtained results to validate the theoretical model. High SE (42.87 dB) and absorption (−14.37) obtained in this work, suggest futuristic applications of n-Ni/PVDF composites for EMI shielding and wave absorption.

Core/shell structured Ni/Fe₃O₄ composites with grain sizes of 200–800 nm were synthesized by using a hydrothermal method. The phase structure, morphology, magnetic and electromagnetic absorption properties of the as-prepared samples were characterized by various analysis techniques. Experimental results revealed that spinel Fe₃O₄ was in situ deposition on the surface of Ni spheres through electrostatic interactions. Moreover, the Ni/Fe₃O₄ mass ratios had a significant influence on the electromagnetic absorption performances. When the mass ratio of Ni/Fe₃O₄ was 1:1, the composites reached an outstanding reflection loss (RL) of $-$48.06dB at 12.96GHz with a thin thickness of 1.8mm. Meanwhile, the effective absorption bandwidth was 5.36GHz (10.72–16.08GHz), covering the X and Ku bands. The enhanced electromagnetic absorption performance of core/shell structured Ni/Fe₃O₄ composites as compared to pure Ni, may be attributed to the multiple interfacial polarization, magnetic exchange coupling resonance and optimal impedance matching. Consequently, core/shell structured Ni/Fe₃O₄ composites would be promising candidates for a wider range of electromagnetic absorption applications.