Enhanced microwave absorption properties of barium ferrites by Zr4+-Ni2+ doping and oxygen-deficient sintering

To achieve excellent microwave absorption properties within the frequency range of 2-18 GHz, Zr4+-Ni2+ co-doped barium ferrites BaFe12-2x(ZrNi)(x)O-19 have been synthesized through a sol-gel process and subsequent sintering. Broadened bandwidth of similar to 6.9 GHz and strong microwave absorption of -59.3 dB is attained for the ferrite with x = 0.6 and sintering in Ar. The excellent microwave absorption properties are attributed to both the effective shifting of resonance peaks by Zr4+-Ni2+ substitution and the enhanced dielectric loss by generating lattice vacancies through the oxygen-deficient sintering process. This work would be helpful to understand the nature of manipulating the resonance behaviors and further improving the microwave absorption efficiency of traditional ferrite absorbers.