Tunable Orientation of Magnetic Chains Enables Absorption‐Dominated Electromagnetic Interference Shielding

Abstract Rapid growth of the electronics industry has led to increased electromagnetic (EM) pollution, necessitating the development of effective EM interference (EMI) shielding materials. Integrating carbon materials with magnetic metals or alloys is a promising approach, but the high conductivity and low skin depth of carbon materials often result in reflection over absorption of EM waves (EMWs). To address this challenge, flexible carbon cloth (CC)‐based composites are developed that allow controlled orientation of magnetic chains (Co, Ni, and CoNi) grown on the CC surface, thereby enhancing absorption‐dominated EMI shielding. By applying an external magnetic field, uniform magnetic chains on the CC substrate with orientation angles of 0°, 60°, and 90° are fabricated. Density Functional Theory calculations reveal that CC@Co exhibits higher polarization loss compared to CC@Ni and CC@CoNi. Reorienting the Co chains from random to parallel (0°) alignment improves the total shielding effectiveness from 34.3 to 35.4 dB and increases the absorptivity from 0.299 to 0.611. This improvement is attributed to enhanced dissipation of incident energy, as evidenced by reduced internal magnetic and electric field strengths. This work demonstrates a method for optimizing the balance between reflection and absorption in flexible shielding materials through structural design.