Electromagnetic Attenuation of Sm‐Doped Alloys Modified by Interface Exchange Coupling and Magnetocrystalline Stress Anisotropy

Abstract The narrow resonance width of magnetic alloys limits their application as wide frequency electromagnetic wave absorbers within the gigahertz range. To address this issue, the study proposes engineering homogeneous interfaces and enhancing anisotropy through Sm doping in FeCo alloy, thereby giving rise to a broadened resonance width and an increased magnetic loss. The results show that Sm‐doping produces abundant grain boundaries and strengthening of the charge transfer (0.16 ev) and magnetic moment (0.34 µ_B), which ultimately heightens the interfacial exchange coupling coefficient by six times. Furthermore, the magnetocrystalline anisotropy constant rises from 4.1 × 10⁵ to 3.0 × 10⁶ J m⁻³, and the stress expands by four fold, owing to the Sm‐doping induced 4f electron spin‐orbit coupling and lattice distortion. Consequently, the frequency of exchange resonance and natural resonance are elevated to 10.4 and 6.4 GHz, separately. Eventually, the alloys with a magnetic loss angle above 0.5 over 7–14 GHz present ultra‐wide electromagnetic wave absorption. This work provides a new approach to homointerface and anisotropy engineering to improve the wide frequency electromagnetic absorption of magnetic alloys.