Temperature‐Induced Self‐Decomposition Doping of Fe₃GeTe₂ to Achieve Ultra‐High Tc of 496 K for Multispectral Compatible Strong Electromagnetic Wave Absorption

Abstract

Fe3GeTe2 provides an ideal system for the study of itinerant ferromagnetism. However, the Curie temperature (Tc) below room temperature limits its further in‐depth research and wide applications. Here, the Tc of 224 K for Fe3GeTe2 is greatly increased to 496 K for Fe3GeTe2/FeTe2/Fe3Ge by temperature‐induced self‐decomposition doping, contributing to improve the electromagnetic response for enhancing the absorption strength and bandwidth and boosting application potentials at higher temperatures. Then, to achieve the multispectral compatible strong absorption, room temperature ferromagnetic dielectric graphene@Fe3GeTe2/FeTe2/Fe3Ge absorber with 3D porous network structure is prepared by synergistic self‐assembly. It has high Tc of 443 K with strong electromagnetic synergistic loss, achieving reflection loss of −61 dB at 12.6 GHz. Moreover, its absorption loss in the terahertz band (0.1–1.6 THz) is 76 dB, and the average loss is greater than 50.4 dB. Furthermore, the absorber is very potential as stealth skin to efficiently reduce satellite RCS with a multi‐angle and multi‐band manner in the gigahertz and terahertz bands, thus achieving the purpose of stealth. Compared with the reported conventional absorbers, the absorber has a multispectral compatible strong absorption performance covering gigahertz and terahertz bands, thus very promising for electromagnetic protection of electromagnetic communication and space vehicles.

Enhanced Polarization Loss toward Lanthanum–Samarium Doping-Encoded Defect Genes of Ferrite for Optimizing Microwave Absorption

“…Consequently, based on the ideal quartic rate equation, the radar detection distance of the missile body worn by stealthy overclothes can be reduced to ≈1/3 of the original. Furthermore, the 3D radar scattering signals of the stealth missile body can be conspicuously attenuated, ascribed to the effective reduction of surficial reflection caused by improved impedance matching, which can be further testified by the gradually growing electric field associated with absorption (Figure F,G) …”

“…Surprisingly, when the incident wave is 0°, the RCS values of the no-stealth and stealth missile bodies are ≈ −20 and ≈ −40 dBm 2 , respectively, in which −20 dBm 2 = 0.01 m 2 and −40 dBm 2 = 0.0001 m 2 according to the equation dBm 2 = 10 × log 10 (m 2 ). 70 Consequently, based on the ideal quartic rate equation, the radar detection distance of the missile body worn by stealthy overclothes can be reduced to ≈1/3 of the original. Furthermore, the 3D radar scattering signals of the stealth missile body can be conspicuously attenuated, ascribed to the effective reduction of surficial reflection caused by improved impedance matching, which can be further testified by the gradually growing electric field associated with absorption (Figure 5F,G).…”

Dielectric Matching by the Unique Dynamic Dipoles in Hybrid Organic/Inorganic Superlattices toward Ultrathin Microwave Absorber

“…From Figure S14b (Supporting Information), the nearly flat platform at 5-18 GHz indicates the preponderance of eddy current loss for TC-85, which contributes to the negative μ″ at 14-18 GHz regarding TC-85 due to the radiation of magnetic energy under the alternating electric field originating from electromagnetic field coupling induced by eddy currents in ferromagnetic TC-85. [48][49][50][51][52] The peak at 2 GHz may signify natural resonance as the vital mechanism for magnetic loss because natural resonance usually occurs at lower frequencies. [53] The evident appearance of the natural resonance peak is possibly due to the low saturation magnetization of TaS 2 /Co(Cp) 2 hybrid and thus the enhanced magnetic anisotropy field.…”

Negative Photoconductivity of Fe3GeTe2 Crystal with Native Heterostructure for Ultraviolet to Terahertz Ultra‐Broadband Photodetection

“…Terahertz timedomain spectroscopy system can get the time-domain spectral signals of the terahertz waves passing through the sample (Figure S4, Supporting Information), and after further analysis and processing, the refractive index, extinction coefficient, dielectric constant, absorption coefficient, and other basic optical parameters of the material can be obtained. [81] During the test, the transmitted signal of the sample is E s (t) and the reference signal of the unplaced sample is E r (t). The time-domain transmission signal underwent a Fourier transform to obtain the amplitude spectrum E s (𝜔), E r (𝜔) and phase spectrum 𝜑 s (𝜔), 𝜑 r (𝜔) of the sample and reference signal.…”