Selective assembly of magnetic nano-antenna for electromagnetic dissipation

Assembly of multiple-component composites into a beneficial multi-shell structure has been demonstrated as an efficient strategy to induce wideband electromagnetic (EM) attenuation in principle. However, structural engineering with selective components remains challenging, hindering the development of high-performance EM absorbers. Herein, a distinctive structure of large-scale magnetic particle-decorated multi-branch Fe@SiO2@Fe is proposed, obtained via an anisotropic magnetic loading strategy to achieve broadband microwave attenuation performance. Adjusting the interaction force equilibrium between magnetic particles and silica, a uniform coating layer composed of bulky magnetic particles on a 3D template is fabricated. The effective microwave bandwidth is broadened by the enhanced magnetic response range with multi-scale magnetic couplings and remarkable hierarchical interfacial polarization in our highly symmetrical structure, reaching 11.5 GHz at a thickness of 2.5 mm. Our component and structural modulation provides a strategy for achieving ultra-broadband EM absorption by anisotropic design.