Synthesis of high-aspect ratio Fe3O4 nanostructures via magnetic field guidance: Toward enhanced microwave absorption performance

One-dimensional materials have extensive applications in the field of functional materials, but the preparation of one-dimensional materials with large aspect ratio remains a challenge. Herein, we demonstrate a single-step magnetic field-assisted hydrothermal approach for synthesizing single-crystalline Fe3O4 nanochains with an exceptional aspect ratio of ∼540:1. Systematic investigations reveal that the magnetic field critically regulates the morphology, crystallinity, growth mode, and magnetic properties of Fe3O4, and its excellent microwave absorption performance. The minimum reflection loss for the 1 T single-crystal chain structure reached −61.94 dB at 8.65 GHz (thickness: 3.56 mm), which is approximately 3.4 times greater than that of the zero-field polycrystalline samples. This research provides a feasible solution for low-cost and large-scale synthesis of 1D Fe3O4 nanostructure with high aspect ratio and offers a practical path for optimizing the performance of microwave absorbing materials.