Zr4+ doping-controlled permittivity and permeability of BaFe12-xZrxO19 and the extraordinary EM absorption power in the millimeter wavelength frequency range
Zr4+ doping-controlled permittivity and permeability of BaFe12-xZrxO19 and the extraordinary EM absorption power in the millimeter wavelength frequency range
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BaFe12-xZrxO19 的 Zr4 掺杂控制介电常数和磁导率以及毫米波长频率范围内非凡的电磁吸收能力
DOI：
10.1039/c6tc03430f
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发表时间：
2016-01-01
影响因子：
6.4
通讯作者：
Du, Piyi
中科院分区：
文献类型：
--
作者：
Liu, Chuyang;Xu, Qiankun;Du, Piyi
采用溶胶-凝胶法合成了Zr ~（4+）掺杂的M型钡铁氧体（BaFe_（12-x）Zr_xO_（19）x = 0 ~ 0.4），具有高介电常数和多谐振磁导率。随着掺杂量的增加，Zr 4+首先取代4f（1）位的Fe 3+，然后取代2b位的Fe 3+，形成单相六方片状钡铁氧体。随着Zr ~（4+）从x = 0增加到0.4，铁氧体的H-a从15.75 kOe减小到8.13 kOe。在18-40 GHz范围内，Zr ~（4+）掺杂的铁氧体的ε ′和ε ″分别从未掺杂时的5.8-5和0.7-0.4增加到7.7-6和3.4-1.5。主要由增强的介电常数贡献，Zr 4+离子掺杂的铁氧体的匹配厚度低至仅类似于1 mm或更低，即比最近报道的那些薄1.5-3倍。在掺杂铁氧体中，复介电常数仍然接近于复磁导率。因此，可以获得类似于-50dB的强反射损耗，并且每单位厚度的电磁（EM）功率的吸收率高达0.156% μ m（-1），即比新颖的吸收材料高2-5倍。多共振磁导率峰源于Fe ~（3+）离子，Fe ~（3+）、Fe ~（2+）和O ~-之间的交换耦合贡献了多个反射损耗峰，从而获得了接近12 GHz的宽带宽（RL < -10 dB），比通常报道的带宽宽2-4倍。因此，Zr 4+掺杂的钡铁氧体有望用作毫米波频率范围内的优良吸收材料。
M-type barium ferrite powders doped with Zr4+ ions (BaFe12-xZrxO19 x = 0-0.4), possessing high permittivity and multi-resonant permeability, were synthesized by the sol-gel process. The single-phase hexagonal plate-like barium ferrites were formed with Zr4+ substituting Fe3+ at the 4f(1) sites initially and then at the 2b sites afterwards with increasing doping content. The H-a of the ferrites decreased from 15.75 kOe to 8.13 kOe with increasing Zr4+ from x = 0 to 0.4. The epsilon' and epsilon" of the ferrite with Zr4+ doping were increased to 7.7-6 and 3.4-1.5 over 18-40 GHz from 5.8-5 and 0.7-0.4 without doping, respectively. Contributed mainly by the enhanced permittivity, the matching thicknesses of the Zr4+ ions doped ferrites were as low as only similar to 1 mm or below, i.e. 1.5-3 times thinner than those reported recently. The complex permittivity was still close to the complex permeability in the doped ferrites. Hence, a strong reflection loss of similar to-50 dB could be attained and the absorptivity of electromagnetic (EM) power per unit thickness reached as high as 0.156% mu m(-1), i.e. 2-5 times higher than those of novel absorbing materials. The multi-resonance permeability peaks originated from Fe3+ ions, and exchange couplings among Fe3+, Fe2+ and O- contributed multiple reflection loss peaks and thus, a broad bandwidth of similar to 12 GHz (RL < -10 dB), which was 2-4 times broader than those normally reported. Consequently, the Zr4+-doped barium ferrites are promising for use as excellent absorbing materials in the millimeter wavelength frequency range.