Effect of manganese addition on the microstructure and electromagnetic properties of YIG

Y3MnxFe4.85-xO12 (x=0, 0.02, 0.04, 0.06, 0.08 and 0.1) garnet ferrites (YMnIG) were prepared by conventional solid-state reaction method in air atmosphere. The effect of Mn addition on the microstructure and electromagnetic properties of YIG were investigated by means of techniques such as X-ray diffraction, scanning electron microscopey, network analyzer, hysteresigraph, magnetic balance and electron paramagnetic resonance spectrometry. Pure garnet phase of Y3Fe5O12 was identified for all the samples, except for minor YFeO3 phase appearing in the sample with x=0.06. The addition of Mn showed little influence on the dielectric constant of YIG, which varied between 14.2 and 14.5. Substituting Mnn+ for Fen+ in YIG decreased the total amount of Fe ions, inhibited the reduction of Fe3+ and promoted the grain growth of garnet phase, which led to the decrease in dielectric loss and coercivity. Because the amount of Mn3+ ions in octahedral sites in- creased with Mn concentration, the saturation magnetization showed a slight decrease firstly and then increased notably. The addition of Mn could also increase the remanence ratio of YIG ferrites by decreasing the magnetostriction constant λ111. Therefore, doping Mn into YIG fer- rites with proper quantity could improve electromagnetic properties of YIG significantly. The YMnIG ferrite with x=0.08, i.e., Y3Mn0.08 Fe4.77O12, showed the optimum electromagnetic properties: εr=14.2, tanδe=1.5×10-4, Hc=36 A/m, 4πMS=192 mT, Br/Bs=0.84, ?H=6.8 KA/m.     

缺铁配方YCaZrIG铁氧体的结构及电磁性能研究

采用传统氧化物法制备了Y2.7Ca0.3Zr0.3Fe4.70-δO12(0≤δ≤0.15,YCaZrIG)石榴石型铁氧体,研究了烧结温度及缺铁量对铁氧体相组成、烧结性能、显微结构及电磁性能的影响.结果表明,制得的YCaZrIG铁氧体均为单相石榴石结构.缺铁越多,越难烧结.缺铁对介电常数影响不大,但可显著降低介电损耗....     

乙炔炭黑和镁铝复合粉对无纺布吸波材料的性能影响

本文研究了乙炔炭黑含量和镁铝复合粉含量分别对无纺布吸波材料电阻值与氧指数的影响。实验结果表明：降低吸波剂中乙炔炭黑的质量有利于提高吸波材料的电阻和电磁损耗;提高无机阻燃剂中镁铝复合粉的含量有利于提高吸波材料的氧指数。     

稀土掺杂的Ba1-xSrxTiO3/MgO材料性能的影响

主要研究了La2O3、Sm2O3、Dy2O3、CeO2等稀土氧化物掺杂的BSTO/MgO铁电移相器材料的调谐性T、低频(10kHz)与高频(2GHz左右)相对介电常数εr和介质损耗tgδ等性能,并对影响机理作了初步探讨.实验结果表明,0.5mol%La2O3掺加的BSTO/MgO系统基本上达到了相控阵移相器在高频下工作的要求10kHz下,tgδ=4×10-4,T=14.6%;2.41GHz下,tgδ=6.7×10-3.     

石榴石型微波铁氧体材料的研究进展

石榴石型铁氧体材料R3Fe5O12(R=Y,Gd)是微波技术中一种重要的功能材料。综述了高性能石榴石型铁氧体、石榴石型铁氧体材料的制备工艺和低温烧结石榴石型铁氧体等方面的研究进展,归纳了研究中存在的问题,同时对其未来的发展趋势做了展望。     

微波石榴石型铁氧体低温烧结的研究进展

石榴石型铁氧体材料是微波技术中一种重要的功能材料.综述了YIG(Y3Fe5O12)多晶铁氧体材料在低温烧结方面的研究现状.总结了实现微波YIG低温烧结的途径.阐述了目前存在的问题,并指出了未来的研究方向.     

微波铁氧体材料的现状与发展

结合国内外微波铁氧体器件的发展趋势,综述了当今微波铁氧体材料领域的发展现状。对于石榴石型材料,低损耗、高功率和低成本等材料配方体系已相应建立。而对于尖晶石类材料,由于磁矩分布范围广,剩磁高等特点,在毫米波以及移相器件中得到广泛应用。对产品性能和产能规模等作了相应的阐述。重点指出开发微带用材料、低互调材料及铁氧体材料工程化的必要性和紧迫性,同时指出了研究思路和方法。