Synergistic enhancement of microwave absorption in ZnFe2O4@PANI composites via magnetic-field-assisted in-situ polymerization.

High-performance microwave-absorbing materials (MAMs) require a precise balance between dielectric and magnetic losses to achieve optimal impedance matching. Herein, we report the synthesis of ZnFe2O4@PANI composites via a magnetic-field-aided in-situ oxidative polymerization method. Systematic characterization reveals that the PANI coating promotes interfacial polarization and conduction loss, while the external magnetic field during synthesis effectively modulates the magnetic ordering and dispersion of the ZnFe2O4@PANI cores. Consequently, the magnetically-assisted ZnFe2O4@PANI composite (Z3) exhibits superior electromagnetic performance, achieving a minimum reflection loss of - 33.4 dB at 8.65 GHz, significantly outperforming the non-magnetic-field-assisted counterpart (Z2, - 18.9 dB). The synergistic enhancement is attributed to the optimized architecture, which concurrently boosts spin correlation and balances magneto-dielectric loss mechanisms. These findings demonstrate that magnetic-field-assisted synthesis is a robust strategy for engineering advanced composites with high-efficiency, frequency-tunable microwave absorption capabilities.