Regulating the phase composition and morphology of iron sulfide via a high magnetic field for controlled electromagnetic wave absorption performance

Abstract

The phase selectivity and morphology of materials are effective strategies for improving electromagnetic wave absorption (EMWA). However, the preparation of EMWA materials with controllable phase composition and adjustable morphology remains a great challenge. Herein, a strategy for phase regulation through a high magnetic field is proposed to achieve controllable adjustment of the phase and morphology of iron sulfide, thereby promoting interface polarization and thus improving EMWA performance. When a high magnetic field is introduced into the reaction, the single Fe₃S₄ phase gradually evolves into FeS₂ owing to the effect of magnetizing energy, forming an Fe₃S₄/FeS₂ composite. With increasing magnetic field intensity, the FeS₂ content gradually increases. In addition, the magnetic field induces the assembly of Fe₃S₄/FeS₂ into a staggered morphology. Because of the regulation of phase and morphology, accompanied by the redistribution of conductive loss and interfacial polarization, the EMWA property of iron sulfide is effectively regulated. The 9 T sample, which demonstrates good impedance matching, exhibits a minimum reflection loss (RL_min) value of −50.31 dB, and the effective absorption bandwidth (EAB) is extended to 4.5 GHz. This work provides valuable guidance and inspiration for the design of phase and morphology controlled by a high magnetic field and demonstrates significant application potential in the regulation of EMWA performance.