In-situ regrowth constructed magnetic coupling 1D/2D Fe assembly as broadband and high-efficient microwave absorber

Abstract Magnetic material performance critically depends on its anisotropic behavior, however, the regulate strategy is still in lack. Herein, a novel 1D/2D anisotropic assembly of two-dimension (2D) magnetic Fe nanosheets supported on one-dimension (1D) Fe chain is successfully constructed as an excellent microwave absorber. By a controllable in-situ regrowth and subsequent reduction strategy, 2D Fe nanosheets radiating out the 1D Fe chain along its axis orientation are successfully converted from an intermediate γ-FeOOH phase. 1D axial Fe chains are self-assembled from isolated Fe nanospheres by the magnetic dipolar interactions. The multi-dimensional 1D/2D Fe exhibits an outstanding absorption performance with reflection loss of −57.3 dB and ultra-wide effective bandwidth of 11.5 GHz (1.9 mm). Integrated large planar anisotropy of 2D Fe nanosheets with anisotropic field of 1D Fe chains, such a hierarchical structure endows the assembly with strong anisotropy for magnetic response enhancement. Reinforced by the ultrathin magnetic nanosheets with high specific surface area, high-density magnetic flux lines construct the large-scale 3D coupling nets, which is confirmed by electron holography. The hierarchical chains cross-link with each other and form 3D conductive networks for enhancing dielectric loss. This finding might provide a novel idea on the design of high-performance microwave absorbers.