Dimensionality-Controlled Magneto-Alignment of Biocarbon toward Superior Microwave Absorption

The macroscopic structure of materials involves two key aspects: dimensionality and spatial arrangement. Understanding how these factors interact to influence material properties is crucial for advancing materials research. Using differently dimensional biocarbon materials as model systems, we demonstrate that high magnetic fields (HMFs) can effectively regulate their macroscopic ordering. The synergistic effects of dimensionality and ordering enhance both electrical conductivity and microwave absorption (MWA). A 4T magnetic field aligns one-dimensional (1D) and two-dimensional (2D) biocarbon materials effectively, yielding orientation order parameters of 0.7 and 0.84, respectively, whereas such alignment is negligible in three-dimensional (3D) materials. Consequently, the electrical conductivity increases by 89% for 1D materials and 742% for 2D materials, with minimal change observed in 3D materials. Furthermore, combining dimensionality with magnetic alignment significantly enhances the MWA of biocarbons. The magnetic alignment extends the effective absorption bandwidth (EAB) of 1D systems to 6.7 GHz (2 mm) while significantly enhancing the absorption capability of 2D systems to achieve a reflection loss of -44.2 dB (3 mm). This study enhances the fundamental understanding of the synergy between dimensionality and spatial arrangement in modulating the microwave performance while providing a basis for optimizing dimensional design in the magnetic field-assisted assembly of ordered materials.