Heterostructure engineering of NiO/carbon-coated Fe NWs with modulated electromagnetic properties for low-frequency microwave absorption

s An electromagnetic parameter inversion strategy using a fixed magnetic permeability can effectively predict and guide the design of low-frequency microwave absorption (MA) properties in magnetic/dielectric composite materials. However, permeability instability caused by material modification hinders precise design. To address this issue, this study adopts heterostructure engineering and first uses the experimentally measured permeability of carbon-coated iron nanowires (Fe NWs@C, abbreviated as FC) as a fixed parameter. Through inversion analysis, the target range of dielectric constants required to achieve an effective 3 GHz absorption bandwidth in the low-frequency band was determined. To address susceptibility to permeability fluctuations during dielectric tuning, antiferromagnetic nickel oxide is introduced to construct Fe NWs@C/NiO (abbreviated as FCNO) heterostructures based on FC via co-deposition and laser ablation. Leveraging NiO's antiferromagnetic nature with zero net magnetic moment and its dielectric properties, precise tuning of the dielectric constant was achieved with minimal disturbance to the original magnetic permeability. Experimental results and data analysis indicate that the FCNO1(the atomic molar ratios of Fe:C:Ni =1:1:0.1) absorber exhibits a minimum low-frequency reflection loss of −45.49 dB at a thickness of 4.8 mm, with an effective absorption bandwidth reaching 3.12 GHz at 5.45 mm, consistent with predictions. Furthermore, the FCNO3(the atomic molar ratios of Fe:C:Ni =1:1:0.3) absorber shows only a 2.06% deviation between the predicted and measured frequencies corresponding to its minimum reflection loss, and only a 4.17% deviation in its effective absorption bandwidth. This work proposes an inversion strategy that introduces antiferromagnetic components to achieve dielectric tuning without perturbing magnetic permeability, providing a viable pathway for optimizing the low-frequency MA performance of magnetic/dielectric composite materials.