材料科学
介孔材料
反射损耗
介电常数
微波食品加热
X射线光电子能谱
兴奋剂
矫顽力
衰减
分析化学(期刊)
光学
核磁共振
光电子学
复合数
凝聚态物理
复合材料
电介质
化学
物理
催化作用
量子力学
生物化学
色谱法
作者
Tao Shang,Qingshan Lu,Luomeng Chao,Yanli Qin,Yun Yang,Guohong Yun
标识
DOI:10.1016/j.apsusc.2017.10.175
摘要
Low-density ordered mesoporous CoFe2O4 (OCFO) and CoLa0.12Fe1.88O4 (OCLFO) are prepared by nanocasting method using mesoporous silica SBA-15 as a hard-template. The crystal structure, surface chemical state, magnetic properties and electromagnetic parameters are characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement, X-ray photoelectron spectroscopy, physical property measurement system and vector network analyzer. The results show that all the samples formed a single phase with cubic spinel structure. Meanwhile OCFO and OCLFO possess a highly ordered mesostructure. Comparing with particle CoFe2O4 (P-CFO), OCFO with high specific surface area exhibits lower magnetic saturation (Ms), higher imaginary part of complex permittivity (ε′′) and imaginary part of the complex permeability (μ′′). The minimum reflection loss (RL) of OCFO reaches −27.36 dB with a matching thickness of 3.0 mm. The enhancement of the microwave absorbing performances of OCFO can be mainly attributed to the good impedance matching, high electromagnetic wave attenuation and multiple reflections of electromagnetic wave originated from the ordered mesoporous structure. The Ms of OCLFO decreases after La3+ doping, while the specific surface area, coercivity value, ε′′ and μ′′ of OCLFO increase. The minimum RL of OCLFO reaches −46.47 dB with a thickness of 3.0 mm, and the effective absorption frequency bandwidth reaches 4.9 GHz.
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