Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials. However, the mechanism of heterogeneous interfaces on microwave absorption is still unclear. In this study, abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard templates. The impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional (0D) hexagonal close- packed (hcp)-face-centered cubic (fcc) Co/two-dimensional (2D) Co(OH)₂ nanosheets@three-dimensional (3D) porous carbon nanosheets (Co/Co(OH)₂@PCN). By controlling the carbonization temperature, the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth (EAB). Accordingly, the EAB of these absorbers were almost greater than 6 GHz (covering the entire Ku-band) in the thickness range of 2.0–2.2 mm except the sample S-1.0-800. As far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss (RL_min) value was −25.8 dB. Moreover, in the far-field condition, the radar cross section (RCS) of S-0.8-700 can be reduced to 19.6 dB·m². We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.

LaMnO₃ perovskite has great potential in microwave absorption at high temperature due to its complex doping effect and super stability. The current research mainly focuses on the doping ratio regulation, while the mechanism of doping effect at high temperature is still lack of sufficient investigation. In this work, La_1−xSr_xMn_1−yFe_yO₃ (LaMnO₃, La_0.7Sr_0.3MnO₃, and La_0.7Sr_0.3Mn_0.8Fe_0.2O₃) nanostructures with different doping sites were successfully prepared by the solid phase reaction method. Then, the high temperature dielectric test samples were obtained by mixing with cordierite (2MgO·2Al₂O₃·5SiO₂ (MAS)). The results showed that the temperature dependence of Mn ion spin state had a significant impact on the high temperature dielectric behavior of La_1−xSr_xMn_1−yFe_yO₃. Particularly, when the thickness is only 1.9 mm, La_0.7Sr_0.3Mn_0.8Fe_0.2O₃/MAS can achieve the widest bandwidth of 4.2 GHz covered the entire X-band (8.2–12.4 GHz) and a minimum reflection loss (RL) value of −17.99 dB at 500 °C. In order to improve the operating temperature of La_0.7Sr_0.3Mn_0.8Fe_0.2O₃/MAS, a cellular array structure was designed by using computer simulation technology (CST) software to introduce magnetic loss. When the outer length of the hexagon is 1 mm and the coating thickness is 1.9 mm, the widest bandwidth covers the X-band and the minimum RL value is −15.35 dB at 800 °C. Therefore, La_0.7Sr_0.3Mn_0.8Fe_0.2O₃ has a great prospect as an efficient high temperature microwave absorber.

ABO₃ perovskites, owning unique properties, have great research prospect in electromagnetic wave absorption field. Normally, doping can significantly regulate the dielectric loss, whereas the magnetic loss can be ignored. In this work, the crystal structure and electromagnetic properties can be regulated systematically by the K, Fe co-doping for LaCoO₃ perovskites (LKCFO) under the condition of fixed F content. In addition, the obtained samples show the obvious interfacial polarization effect on accounting to the small size effect, which is conducive to the effective microwave absorption. By analyzing the evolution of the positron annihilation lifetime and the first-principles calculation of the oxygen density of states for the series of LKCFO perovskites, it is found that the charge transport characteristics will be controlled by the point defect generated by allelic doping. The point defect content decreases and then increases as the doping level rises. The prepared perovskite exhibits the lowest defect density and the largest dielectric loss capability, which indicates that the lower point defects promote electron migration and thus enhance the dielectric loss; thus, the electromagnetic wave absorption bandwidth up to 6.2 GHz is reached. In contrast, both insufficient and excessive K doping are detrimental to the enhancement of microwave absorption. Especially, the practical application value was investigated using Computer Simulation Technology (CST) simulations. The LKCFO-2 exhibits the smallest RCS value (below −10 dBm²) at almost −90°– 90° with a thickness of 2 mm, providing an effective method for study excellent microwave absorption and scattering property.

As the growing criterion of electromagnetic wave (EMW)absorption materials, micro/nano-scale magnetic materials are drawing more and more attention for their unique features compared to bulky absorbers. Generally, the complex permeability of micro/nano-scale magnetic absorbers varies in a relatively narrow range, whatever for the storage of magnetic energy or the dissipation of magnetic energy. If so, how the small variation of permeability affects the ultimate performances is still unclear. Here, a strategy of electromagnetic parameters regulation for the magnetic materials is applied to understand the loss contribution in micro/nano- scale magnetic absorbers. After analyzing the evolution of electromagnetic maps of ten ferrosoferric oxide samples, it can be found that the dissipation contribution of permeability for magnetic materials is weaker than that of permittivity, in spite of its significant role in determining the impedance matching characteristics. In summary, this work systematically explores the loss contribution in micro/nano-magnetic absorbers for the first time, which is of great importance in designing and optimizing the microwave absorption properties of magnetic absorbers.

As electromagnetic absorbers with wide absorption bandwidth are highly pursued in the cutting-edge electronic and telecommunication industries, the traditional dielectric or magnetic bulky absorbers remain concerns of extending the effective absorption bandwidth. In this work, a dual-principle strategy has been proposed to make a better understanding of the impact of utilizing conductive absorption fillers coupled with implementing artificial structures design on the absorption performance. In the comparison based on the microscopic studies, the carbon nanotubes (CNTs)-based absorbers are confined to narrow operating bandwidth and relatively fixed response frequency range, which can not fulfill the ever-growing demands in the application. With subsequent macroscopic structure design based on the CNTs-based dielectric fillers, the artificial patterns show much more broadened absorption bandwidth, covering the majority of C-band, the whole X-band, and Ku-band, due to the tailored electromagnetic parameters and more reflections and scatterings. The results suggest that the combination of developing microscopic powder/bulky absorbers and macroscopic configuration design will fundamentally extend the effective operating bandwidth of microwave.

A symmetrical Fe₂O₃/BaCO₃ hexagonal cone structure having a height of 10 μm and an edge length of ~4 μm is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe₂O₃ was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2–18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO₃ likely played a vital role in the excellent electromagnetic absorption properties described in this research.