A superior microwave absorption material: Ni2+ -Zr4+ Co-Doped barium ferrite ceramics with large reflection loss and broad bandwidth

Large reflection loss and wide bandwidth are significant targets, determining the microwave absorption ability. However, it is still a challenge to simultaneously satisfy the two conditions. As a multifunctional material, BaFe12O19 possess excellent electromagnetic properties in the microwave frequency band. Due to the natural resonance phenomenon of the material, BaFe12O19 can produce a large magnetic loss which correlates with Fe3+ content, and the microwave absorption characteristics of barium ferrite can be modulated by ion doping. As a typical magnetic metal, Ni coupled with high-valence state Zr4+ doping helps to produce double resonance peaks. In this work, Ni2+ -Zr4+ co-doping M-type barium ferrites (BaFe12-2xNixZrxO19, BNZFO-x, x = 0-0.8) were prepared conveniently by solid-state reaction method. Several necessary measurements to characterize its microwave absorption property have been operated such as morphology, magnetic performance and electromagnetic parameters. The results show that reflection loss and bandwidth can be simply tuned by tailoring Ni2+ - Zr4+ content. The reflection loss peak drifts from 18 GHz to 9.76 GHz, which involves a half of the studied frequency range. The maximum reflection loss achieves - 60.6 dB and the corresponding bandwidth over - 10 dB is 7.68 GHz for BNZFO-0.6 ceramic with only 2.1 mm thickness. Thus, the doping of Ni2+ -Zr4+ ion pairs is beneficial to improve the absorbing properties of the material, and the superior microwave absorption property may originate from its inner double natural resonance in micro-scale. The excellent microwave absorption properties suggest that BNZFO-x is a promising candidate applied for designing electromagnetic shielding devices.