Anisotropy-Engineered Porous Magnetic Microspheres for Low-Frequency Electromagnetic Absorption.

Abstract

Magnetic microspheres with tunable magnetic characteristics and structural versatility are promising for electromagnetic (EM) functional materials, yet their development remains limited by the trade-off between magnetic performance and material density. Here, we report anisotropy-engineered porous magnetic microspheres constructed through an ion-engineering strategy, enabling simultaneously enhanced magnetic loss and reduced density without compromising magnetic functionality. Inverted-cone pores introduce strong structural anisotropy, driving magnetic moment reconfiguration, complex domain evolution, and directional magnetic interactions. This anisotropic porous framework further promotes interparticle magnetic coupling and establishes a multiscale magnetic response network for efficient EM energy dissipation. Importantly, tuning the pore aperture enables precise regulation of magnetic response, providing additional structural and functional versatility. Unlike conventional hollow or core-shell architectures, this design preserves the magnetic core while integrating anisotropic porosity, enabling concurrent enhancement of magnetic loss, interfacial polarization, and magnetic coupling. Consequently, the optimized ICFM-3 achieves an extended effective absorption bandwidth (EAB) of 2.88 GHz (5.12-8.00 GHz) at a mere 2.8 mm thickness, demonstrating efficient attenuation performance in the C-band. These findings establish anisotropy engineering as a general strategy for lightweight high-performance EM functional materials.