Electronic structure and absorption mechanism of Fe-doped Y_0.9Sr_0.1CoO₃ perovskite microwave absorbers

YCoO₃ has unique advantages in functional applications owing to its exceptional lattice stability, valence adaptability, and environmental resistance; however, its potential for microwave absorption remains largely unexplored. In this study, Y_0.9Sr_0.1Co_1−xFe_xO₃ (x = 0–0.2) perovskite absorbers were synthesized via a sol–gel method, which demonstrated superior microwave absorption performance. Oxygen vacancy engineering facilitates Co redox cycling, significantly enhancing oxygen ion mobility and conductivity loss. First-principles calculations revealed that Fe³⁺doping not only intensifies crystal polarization but also improves magnetic properties, thereby synergistically optimizing dipole polarization and magnetic losses. Additionally, the nanoscale particle morphology enhances the interfacial polarization effects. The optimal composition (x = 0.1) achieves an effective absorption bandwidth (EAB) of 5.71 GHz with a reflection loss (RL) of −47.18 dB at a thickness below 1.8 mm, demonstrating a significant enhancement over that of the undoped material. This work provides new insights into the design of ultrathin, high-performance absorbers while elucidating the fundamental loss mechanisms in perovskite-based systems.