Complex permittivity, permeability, and microwave absorption of Zn- and Ti-substituted barium ferrite by citrate sol–gel process

2002 ◽  
Vol 96 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Zhang Haijun ◽  
Liu Zhichao ◽  
Ma Chengliang ◽  
Yao Xi ◽  
Zhang Liangying ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Complex Permittivity ◽  
Barium Ferrite ◽  
Sol Gel ◽  
Sol Gel Process

Magnetically anisotropic barium ferrite thin films on sapphire by sol–gel process

2010 ◽  
Vol 518 (12) ◽  
pp. 3342-3344 ◽  
Author(s):  
Hao Tang ◽  
Wenxu Zhang ◽  
Bin Peng ◽  
Wanli Zhang
Keyword(s):  
Thin Films ◽  
Barium Ferrite ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Ferrite Thin Films

Preparation and Microwave-Absorption Property of SiO2-SiC-Based Composites

2010 ◽  
Vol 434-435 ◽  
pp. 231-234
Author(s):  
Li Guan ◽  
Bing Bing Fan ◽  
Ming Liang Li ◽  
He Jing Wen ◽  
Kai Li ◽  
...  
Keyword(s):  
Solid State ◽  
Microwave Absorption ◽  
Solid State Reaction ◽  
Sol Gel ◽  
Composite Particles ◽  
Network Analyzer ◽  
Epoxide Resin ◽  
Maximum Reflectivity ◽  
Sol Gel Process ◽  
Sic Composites

SiO2-SiC composite particles were prepared using a sol-gel process. BaTiO3 powders were synthesize through solid-state reaction. They were mixed as microwave absorbents with Fe3O4 powders to obtain the complex absorption. Epoxide resin (EP) was used as matrix and solidified with the mixtures. The techniques of DSC-TG, XRD were used to characterize the composite particles and the obtained compacts. A vector network analyzer was used to measure the reflectivity of the SiO2-SiC-based composites. The effects of the aborbents’ contents on the reflection of the microwave absorption materials were disscussed. It was found that SiO2-SiC composites could be prepared using sol-gel process and BaTiO3 powders could be synthesize through solid-state reaction. The results indicated that SiO2-SiC composite is contribute to absorb microwave, where SiO2-SiC: BaTiO3: Fe3O4 = 6:2:2 (vol %), the frequency region in which the maximum reflectivity is more than -10 dB is 5.4-7.6 GHz.

scholarly journals A Neutron Diffraction Investigation of High Valent Doped Barium Ferrite With Super-wide Tunable Microwave Absorption

2021 ◽  
Author(s):  
J. Li ◽  
Yang Hong ◽  
San He ◽  
Weike Li ◽  
Han Bai ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Microwave Absorption ◽  
Barium Ferrite ◽  
Sol Gel ◽  
Double Resonance ◽  
Low Frequency ◽  
Anisotropy Field ◽  
Wide Band ◽  
Crystal Anisotropy ◽  
High Valent

Abstract The Barium ferrite BaTixFe12-xO19 (x = 0.2, 0.4, 0.6, 0.8) ceramics doped by Ti4+ (BFTO-x) were synthesized by a modified sol-gel method. The crystal structure and magnetic structure of the samples were determined by neutron diffraction, and confirm that the BFTO-x ceramics were high quality single phase with sheet micro-structure. With x increasing from 0.2 to 0.8, the Ms decreases gradually but the change of Hc is complex under the synergy of the changed grain size and the magnetic crystal anisotropy field. Relying on the high valence of Ti4+, double resonance peaks are obtained in the curves of μ′′ and the resonance peaks could move towards the low frequency with the increase of x, which facilitate the samples perform an excellent wide-band modulation microwave absorption property. In the x = 0.2 sample, the maximum reflection loss can reach –44.9 dB at the thickness of only 1.8 mm, and the bandwidth could reach to 5.28 GHz at 2 mm when the RL is less than –10 dB. All the BFTO-x ceramics show excellent frequency modulation ability varying from 18 GHz (x = 0.8) to 4 GHz (x = 0.4), which covers 81% of the investigated frequency in microwave absorption field.

Preparation, Dielectric and Magnetic Properties of Barium-Ferrite-Containing Microcrystalline Glass Ceramic by Citrate Sol-Gel Process

2007 ◽  
Vol 280-283 ◽  
pp. 457-460 ◽  
Author(s):  
Hai Jun Zhang ◽  
Xiao Lin Jia ◽  
Xi Yao ◽  
Liang Ying Zhang
Keyword(s):  
Dielectric Constant ◽  
Barium Ferrite ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Complex Dielectric Constant ◽  
Complex Permeability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Scanning Electron

Four kinds of barium-ferrite-containing microcrystalline glass ceramics, such as BaFe12O19/SiO2, BaFe12O19/SiO2-B2O3, BaFe12O19/SiO2-B2O3-K2O and BaFe12O19/SiO2-Al2O3-K2O were prepared by citrate sol-gel process, in which inceptive formation temperatures varied from 850°C to 1100°C. The complex dielectric constant and complex permeability of those glass ceramics were measured at 0.1-5.0GHz, and the frequency dependence of complex dielectric constant and permeability was studied. The microcrystalline glass ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM).

Synthesis and microwave absorption enhancement of graphene@Fe3O4@SiO2@NiO nanosheet hierarchical structures

Nanoscale ◽  
2014 ◽  
Vol 6 (6) ◽  
pp. 3157-3164 ◽  
Author(s):  
Lei Wang ◽  
Ying Huang ◽  
Xu Sun ◽  
Haijian Huang ◽  
Panbo Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Hydrothermal Reaction ◽  
Sol Gel ◽  
Hierarchical Structures ◽  
Absorption Enhancement ◽  
Sol Gel Process ◽  
Nio Nanosheets

Hierarchical structures of graphene@Fe3O4@SiO2@NiO nanosheets were prepared by combining the versatile sol–gel process with a hydrothermal reaction.

scholarly journals A neutron diffraction investigation of high valent doped barium ferrite with wideband tunable microwave absorption

2022 ◽  
Vol 11 (2) ◽  
pp. 263-272
Author(s):  
Jun Li ◽  
Yang Hong ◽  
San He ◽  
Weike Li ◽  
Han Bai ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Microwave Absorption ◽  
Barium Ferrite ◽  
High Performance ◽  
Sol Gel ◽  
Double Resonance ◽  
Low Frequency ◽  
Anisotropy Field ◽  
Crystal Anisotropy ◽  
High Valent

AbstractThe barium ferrite BaTixFe12−xO19 (x = 0.2, 0.4, 0.6, 0.8) (BFTO-x) ceramics doped by Ti4+ were synthesized by a modified sol—gel method. The crystal structure and magnetic structure of the samples were determined by neutron diffraction, and confirm that the BFTO-x ceramics were high quality single phase with sheet microstructure. With x increasing from 0.2 to 0.8, the saturation magnetization (Ms) decreases gradually but the change trend of coercivity (Hc) is complex under the synergy of the changed grain size and the magnetic crystal anisotropy field. Relying on the high valence of Ti4+, double resonance peaks are obtained in the curves of the imaginary part of magnetic conductivity (μ″) and the resonance peaks could move toward the low frequency with the increase of x, which facilitate the samples perform an excellent wideband modulation microwave absorption property. In the x = 0.2 sample, the maximum reflection loss (RL) can reach −44.9 dB at the thickness of only 1.8 mm, and the bandwidth could reach 5.28 GHz at 2 mm when RL is less than −10 dB. All the BFTO-x ceramics show excellent frequency modulation ability varying from 18 (x = 0.8) to 4 GHz (x = 0.4), which covers 81% of the investigated frequency in microwave absorption field. This work not only implements the tunable of electromagnetic parameters but also broadens the application of high-performance microwave absorption devices.

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