Multiple nature resonance behavior of BaFexTiO19 controlled by Fe/Ba ratio and its regulation on microwave absorption properties

To achieve excellent microwave absorption properties around atmospheric window of 35 GHz, Ti4+ ions doped barium ferrites BaFexTiO19 with Fe/Ba ratio of 11:1-9.5:1 are synthesized by a sol-gel progress. Broad bandwidth of similar to 11 GHz and strong microwave absorption of similar to -37 dB are attained around 35 GHz with thickness of similar to 2.8 mm and Fe/Ba ratio of 10:1-9.5:1. The correlation between Fe/Ba ratio and the multi-resonance behavior of BaFexTiO9 is fully revealed. It is found that the resonance peak shifts to lower range and the peak ascribed to exchange coupling between Fe2+ and Fe3+ enhances gradually with Fe/Ba ratio decreasing from 11:1 to 10:1-9.5:1. The impedance matching principle calculations combined with quarter-wavelength theory give the required permeability of the barium ferrites for considerable microwave absorption properties, and fully confirm the experimental results. This study would be beneficial to both understanding the nature of the multiple resonance behavior impacting on the microwave absorption properties and designing the future high-efficiency microwave absorbers. (C) 2018 Elsevier B.V. All rights reserved.