Parallel-Orientation-Induced Strong Resonances Enable Ni Submicron-Wire Array: an Ultrathin and Ultralight Electromagnetic Wave Absorbing Material

Soft magnetic micro/nanostructures are highly desirable for pursuing excellent magnetic properties and electromagnetic wave (EMW) absorption performance. However, their magnetic loss at high frequency is usually very low due to the sharp drop of permeability, and thus results in a heavy loading in matrix and a large layer thickness, which are not conductive to the development of ultralight and ultrathin EMW absorbers. Here, an ultralight and ultrathin EMW absorber based on a parallel Ni wire array are reported, and an orientation-enhanced strategy to improve EMW absorption performance is proposed. Combining with the finite element simulation, it is found that the parallel orientation of Ni wires with a capacitor-like structure enhances the interfacial polarization, thereby improving dielectric loss. The strong shape anisotropy caused by orientation increases magnetic loss by enhancing magnetic resonances, which further improves impedance matching. The parallel Ni wire array exhibits excellent EMW absorption and achieves the largest specific reflection loss (reflection loss/(thickness × loading)) among magnetic wire-based absorbers.