Enhanced electromagnetic absorption properties of Fe-doped Sc2Si2O7 ceramics

Abstract

Doping transition metal elements in a crystal causes distortion and defects in the lattice structure, which change the electronic structure and magnetic moment, thereby adjusting the electrical conductivity and electromagnetic properties of the material. Fe-doped Sc2Si2O7 ceramics were synthesized using the sol-gel method for application to microwave absorption. The effect of Fe-doped content on the electromagnetic (EM) and microwave absorption properties was investigated in the Ku-band (12.4–18 GHz). As expected, the dielectric and magnetic properties improve substantially with increasing Fe content. Fe doping causes defects and impurity levels, which enhance polarization loss and conductance loss, respectively. Fe replaces Sc atoms in the ScO6 octahedral structure, creating a difference in spin magnetic moments, which increases the magnetic moment. Moreover, the magnetic coupling of Fe and O atoms occurs at the Fermi level, which benefits magnetic loss. In particular, when the Fe content is 6%, the fabricated Fe-doped Sc2Si2O7 ceramics show an absorption property with absorption peaks located at 14.5 GHz and a minimum reflection loss (RLmin) of −12.8 dB. Therefore, Fe-doped Sc2Si2O7 ceramics with anti-oxidation and good microwave absorption performance have a greater potential for application in high-temperature and water-vapor environments.