Hierarchical design of FeCo-based microchains for enhanced microwave absorption in C band

Microwave absorbing materials (MAMs) has been intensively investigated in order to meet the requirement of electromagnetic radiation control, especially in S and C band. In this work, FeCo-based magnetic MAMs are hydrothermally synthesized via a magnetic-field-induced process. The composition and morphology of the MAMs are capable of being adjusted simultaneously by the atomic ratio of Fe²⁺ to Co²⁺ in the precursor. The hierarchical magnetic microchain, which has a core–shell structure of two-dimensional Fe_xCo_1−xOOH nanosheets anchored vertically on the surface of a one-dimensional (1D) Co microchain, shows significantly enhanced microwave absorption in C band, resulting in a reflection loss (R_L) of lower than −20 dB at frequencies ranging from 4.4 to 8.0 GHz under a suitable matching thickness. The magnetic coupling of Co microcrystals and the double-loss mechanisms out of the core-shell structure are considered to promote the microwave attenuation capability. The hierarchical design of 1D magnetic MAMs provides a feasible strategy to solve the electromagnetic pollution in C band.