Regulating Local Coordination Environment of Single‐Atom Co Absorbers for Dielectric‐Magnetic Dual Loss Modulation

Single-atom materials with well-defined microstructures offer unique opportunities for revealing electromagnetic energy dissipation mechanisms. However, research on the optimization of local electronic states to achieve dielectric-magnetic collaborative losses remains rare. Herein, a dipole-spin synergistic regulation was realized in cobalt single-atom (Co-SA) absorbers through atomic-scale coordination engineering. Experimental and theoretical analyses revealed that asymmetric coordination facilitates enhanced dipole polarization, thereby improving dielectric loss, while the low-spin to high-spin transition increases the magnetic moment, resulting in strengthened magnetic loss. This dielectric-magnetic synergistic regulation constructs superior atomic-level absorption centers, enabling outstanding electromagnetic wave absorption (EWA) with a minimum reflection loss of -54.87 dB and an effective absorption bandwidth of 5.36 GHz. This work demonstrates a scalable approach for the precise design and optimization of high-performance EWA materials and offers a new insight into the relationships between the single-atom coordination environment and the EWA performance.