Tuning of electromagnetic wave absorbing properties in Fe-deficient SrFe9.6-xCo1.2Ti1.2O19 hexaferrite-epoxy composites

Abstract We report the tunable electromagnetic (EM) wave absorption properties of Fe-deficient SrFe9.6-xCo1.2Ti1.2O19 hexaferrite–epoxy composites. SrFe9.6-xCo1.2Ti1.2O19 hexaferrite powders were prepared via solid-state reaction routes. It was observed that Sr–Ti-rich second phases were formed as x increased, i.e., the Fe content decreased. The ferromagnetic resonance (FMR) frequency of the composites gradually decreased from 8.8 GHz to 4.8 GHz with increasing x, and accordingly, the EM absorption frequency range also gradually changed. The gradual FMR frequency shift was attributed to the compositional shift in the mother phase. It is predicted that the Fe deficiency caused a decrease in the magnetocrystalline anisotropy, and in turn, it shifted the FMR frequency and modified the corresponding EM absorbing properties. All the samples demonstrated a high EM absorption performance with the lowest reflection loss of