Dispersing Magnetic Nanoparticles into Staggered, Porous Nano‐Frameworks: Weaving and Visualizing Nanoscale Magnetic Flux Lines for Enhanced Electromagnetic Absorption

Abstract By dispersing magnetic materials within various nanoscale structural frameworks, a complex and weavable magnetic network of nanoscale magnetic fields is created. This network not only systematically reconstructs interactions with external electromagnetic fields but also inversely adjusts its magnetic properties, potentially leading to anomalous or enhanced magnetic behaviors. However, the challenges lie in finding an effective nano‐framework capable of efficiently regulating magnetic flux lines and visualizing these reconstructed fields at the nanoscale. In this study, magnetic Co nanoparticles are strategically dispersed into a meticulously layered nanoporous framework with the bottom and upper nanopores exhibiting a staggered arrangement. The staggered nanoporous structure intricately shapes the magnetic flux lines into a Chinese knot shape, significantly altering its magnetic characteristics. The innovative use of advanced in situ magnetic holography, coupled with magnetic simulation calculations, has been instrumental in visualizing these modifications to the magnetic flux lines. Such a transformation remarkably enhances the material's efficacy in absorbing electromagnetic waves, covering the Ku band with remarkable efficiency even at a minimal thickness of 1.7 mm. Looking ahead, these breakthroughs not only provide a roadmap for developing more efficient electromagnetic wave absorbers but also open up new possibilities in manipulating magnetic properties for various advanced technological applications.