Exceptional magnetic shielding via ultra-low-remanence co-based amorphous alloys engineered by atomic ordering

Ubiquitous electromagnetic signals enable modern information exchange but also cause radiation, interference, and data security risks. Shielding low-frequency magnetic fields (f < 100 kHz) remains challenging because conventional materials exhibit high residual magnetization that weakens shielding performance. Here, ultra-low residual magnetization in Co-based amorphous alloys is achieved through atomic ordering induced by multi-step rotating magnetic field (MS-RMF) annealing. The alloys show ultra-low coercivity (0.147 A/m), residual magnetic field of ∼50 nT, and a maximum permeability of ∼400,000, resulting in a 70% improvement in magnetic shielding effectiveness by reducing magnetic anisotropy and enhancing domain wall mobility.