scholarly journals Structural, magnetic, and gigahertz-range electromagnetic wave absorption properties of bulk Ni–Zn ferrite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Derakhshani ◽  
E. Taheri-Nassaj ◽  
M. Jazirehpour ◽  
S. M. Masoudpanah
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Magnetic Loss ◽  
Contour Plot ◽  
X Ray Diffraction ◽  
Minimum Thickness ◽  
Absorption Properties ◽  
Solid State Route ◽  
Zn Ferrite

AbstractNickel–zinc ferrite (Ni0.5Zn0.5Fe2O4) powders were prepared by the conventional solid-state route and sintered at 1100 and 1300 °C for utilization as a tile electromagnetic wave absorber. Structural, magnetic, and microwave absorption properties were investigated by characterization techniques of X-ray diffraction, thermogravimetric analysis, Raman spectroscopy, electron microscopy, vibrating sample magnetometry, and vector network analyzer. The samples sintered at 1300 °C showed high magnetic saturation of 87 emu/g and low coercivity of 4 Oe. Electromagnetic investigations exhibit high reflection losses up to − 48.1 dB at certain high and low gigahertz frequencies, as clearly depicted in the 3D contour plot. The optimized condition between reflection loss, thickness, and bandwidth revealed a reflection loss of about − 36.1 dB at the matching thickness of 3.7 mm for the X-band. Furthermore, the effective working bandwidth at − 10 dB was up to ~ 7.1 GHz for the minimum thickness of 4.3 mm, which thoroughly covered the C-band. The microwave absorption performance of the well-sintered Ni–Zn ferrite was attributed to the incorporation of dielectric and magnetic loss mechanisms in which the magnetic part prevails.

Fabrication and Microwave Characteristics of Fe3O4/C Composites

2012 ◽  
Vol 430-432 ◽  
pp. 146-149 ◽  
Author(s):  
Wen Wang ◽  
Cheng Guo Wang ◽  
Yu Guo
Keyword(s):  
Microwave Absorption ◽  
Magnetic Loss ◽  
Carbon Matrix ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Heat Treated ◽  
Different Temperatures ◽  
Microwave Characteristics

Fe3O4/C composites were prepared by using Fe and polyacrylonitrile (PAN) as precursors, and then heat-treated at temperatures of 600,700 and 800 °C, respectively. The phase composition of the composites at different temperatures was analyzed by X-ray diffraction, and Fe reacted with O from PAN to form Fe3O4, which contributed to the improvement of magnetic loss of the carbon matrix. Electromagnetic and microwave absorption properties of the composites were investigated. The results show that the values of real and imaginary part of permittivity were all increased as the temperature increasing, and also the microwave absorption capability was improved.

Preparation and Electromagnetic Wave Absorption Properties of Core-Shell Ni/TiO2 Microspheres

2014 ◽  
Vol 602-603 ◽  
pp. 762-766
Author(s):  
Biao Zhao ◽  
Bing Bing Fan ◽  
Hao Chen ◽  
Xiao Xuan Pian ◽  
Bin Bin Wang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Magnetic Loss ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
X Ray ◽  
Wave Absorption ◽  
Chloride Hexahydrate

The composite microspheres with Ni cores and amorphous TiO2 shells (Ni@TiO2) were synthesized by a one-pot solvothermal method at 180°C for 15 h, which used nickel chloride hexahydrate as Ni source andtetrabutyl orthotitanate as Ti source. The Ni/TiO2 core/shell composites were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX). A possible formation mechanism of core-shell Ni/TiO2 was proposed. Furthermore, the microwave absorption properties of these microspheres were investigated in terms of complex permittivity and permeability. The minimum reflection loss is-29.5 dB at 14.4 GHz for a layer of 4.0 mm thickness. Such phenomenon is attributed to the synergy effect between magnetic loss of Ni core and dielectric loss of amorphous TiO2 shell. The enhanced microwave absorption properties are also believed to be due to the unique coreshell structure. All results indicate that these Ni@TiO2 microspheres may be attractive candidate materials for electromagnetic wave absorption applications.

Microwave Absorption Properties of Monovalent Doped La0.85Ag0.15MnO3 Manganites Prepared by Solid State Method

2021 ◽  
Vol 317 ◽  
pp. 22-27
Author(s):  
Nur Ain Athirah Che Apandi ◽  
Norazila Ibrahim ◽  
Zaiki Awang ◽  
Ra'ba'ah Syahidah Azis ◽  
Muhammad Syazwan Mustaffa ◽  
...  
Keyword(s):  
Solid State ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Magnetic Loss ◽  
Domain Wall Motion ◽  
Rhombohedral Structure ◽  
Absorption Properties ◽  
Solid State Method ◽  
Microwave Absorption Properties ◽  
State Method

The microwave absorption properties of La0.85Ag0.15MnO3 prepared by solid state method was investigated. Analysis of X-ray diffraction data using a refinement technique confirmed the rhombohedral structure of the samples. The microstructure of the sample characterised from field emission scanning electron microscope micrographs showed irregular grain shapes with grain sizes ranging from 800 to 1500 nm. M-H curves revealed the weak ferromagnetic properties of the sample at room temperature. The real and imaginary parts of permittivity and permeability as well as microwave reflection loss were measured by a vector network analyser in the 8–18 GHz frequency range. The La0.85Ag0.15MnO3 sample showed a minimum reflection loss of –57.2 dB at 16.41 GHz, with a –10dB bandwidth (corresponding to reflection loss below –10 dB, or 90% absorption) of 2.67 GHz. The microwave absorption of La­­­­0.85Ag0.15MnO3 mainly arises from the conduction loss and domain wall motion which contributed to dielectric loss and magnetic loss, respectively.

scholarly journals Nanostructured Barium Titanate/Carbon Nanotubes Incorporated Polyaniline as Synergistic Electromagnetic Wave Absorbers

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Lujun Yu ◽  
Yaofeng Zhu ◽  
Chen Qian ◽  
Qiang Fu ◽  
Yongzhen Zhao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Wave ◽  
Barium Titanate ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Network Structures ◽  
Conductive Network ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Absorption

The three-dimensional (3D) conductive network structures formed by barium titanate/carbon nanotubes incorporated polyaniline were favorable for strengthening electromagnetic absorption capability. Herein, an easy and flexible method consisting of sol-gel technique, in situ polymerization, and subsequent mechanical method have been developed to prepare the barium titanate/carbon nanotubes incorporated polyaniline (CNTs/BaTiO3/PANI or CBP) ternary composites. The dielectric properties and microwave absorption properties of CNTs/BaTiO3/PANI composites were investigated in the frequency range of 2–18 GHz by vector network analyzer. Interestingly, it is found that the CNTs/BaTiO3/PANI composites with 3D conductive network structures presented outstanding electromagnetic absorption properties, which may be attributed to the high impedance matching behavior and improved dielectric loss ability and novel synergistic effect. Additionally, it also can be supposed that the “geometrical effect” of composite was more beneficial to absorbing the incident electromagnetic wave. The CNTs/BaTiO3/PANI composite (the mass ratio of CNTs/BaTiO3to PANI is 2 : 3) exhibits the best microwave absorption properties, of which the minimum reflection loss value can reach −30.9 dB at 8 GHz and the absorption bandwidth with a reflection loss blew −10 dB ranges from 7.5 to 10.2 GHz.

ZnS nanowall coated Ni composites: facile preparation and enhanced electromagnetic wave absorption

RSC Advances ◽  
2014 ◽  
Vol 4 (105) ◽  
pp. 61219-61225 ◽  
Author(s):  
Biao Zhao ◽  
Gang Shao ◽  
Bingbing Fan ◽  
Wanyu Zhao ◽  
Yajun Xie ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Facile Preparation

The microwave absorption properties of ultrathin ZnS wall-coated Ni composites were superior to those of Ni microspheres and ZnS particles.

Synthesis, Characterization, and Microwave Absorption Properties of SrFe12O19 Ferrites and FeNi3 Nanoplatelets Composites

2010 ◽  
Vol 148-149 ◽  
pp. 893-896 ◽  
Author(s):  
Ze Yang Zhang ◽  
Xiang Xuan Liu ◽  
You Peng Wu
Keyword(s):  
Electron Microscopy ◽  
Microwave Absorption ◽  
Composite Coatings ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Filling Fraction ◽  
Microwave Absorption Properties ◽  
Phase Reduction ◽  
Transmission Electron

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.

Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai
Keyword(s):  
Particle Size ◽  
Sinter Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Sol Gel ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Measured Frequency Range ◽  
Maximum Reflection Loss

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

Prepared and Microwave-Absorption Properties of BN Coated Ni Nanocapsules

2010 ◽  
Vol 663-665 ◽  
pp. 1252-1255 ◽  
Author(s):  
Gui Mei Shi ◽  
Shu Lian ◽  
Ge Song ◽  
Jin Bing Zhang
Keyword(s):  
Reflection Loss ◽  
Electromagnetic Properties ◽  
Mechanochemical Reaction ◽  
Network Analyzer ◽  
Absorber Thickness ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Transmission Electron

BN coated Ni nanocapsules were prepared by arc evaporating Ni-B amorphous alloy powders synthesized by a mechanochemical reaction, and their microstructure, surface component as well as electromagnetic properties (2-18 GHz) were investigated by means of high-resolution transmission electron microscopy, X-ray diffraction , photoluminescence spectra (PL) and a network analyzer, respectively. The reflection loss R (dB) of the nanocapsules less than -20 dB was obtained in the frequency range of 4.3-18 GHz for an absorber thickness of 1.4-6 mm. An optimal reflection loss of -32.0 dB was reached at 13 GHz with an absorber thickness of 2 mm. The microwave absorptive mechanisms of BN-coated Ni nanocapsule absorbent were discussed.

Symmetrical polyhedron-bowl Co/CoO with hexagonal plate to forward electromagnetic wave absorption ability

CrystEngComm ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 816-826 ◽  
Author(s):  
Biao Zhao ◽  
Yang Li ◽  
Junwei Liu ◽  
Lei Fan ◽  
Ka Gao ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Hexagonal Plate

The symmetrical polyhedron-bowl structured Co/CoO displays enhanced microwave absorption properties.

Large-Scale Synthesis and Microwave Absorption Properties of CoFe2O4/ Co0.4Zn0.6Fe2O4 Hollow Nanospheres

2015 ◽  
Vol 645-646 ◽  
pp. 126-131
Author(s):  
Qing Guo Ren ◽  
Xiao Jing Qiao ◽  
Yan Li ◽  
Zhi Gang Sun ◽  
Xiao Dang Guo ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Large Scale ◽  
Average Diameter ◽  
Hollow Nanospheres ◽  
Magnetic Studies ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Glycol Solution

Monodisperse CoFe2O4and Co0.4Zn0.6Fe2O4hollow nanospheres were synthesized in large scale by solvothermal method in ethylene glycol solution. The structure, shape and size of the samples were investigated by Fourier Transform infrared, X-ray powder diffraction and scanning electron microscopy. The results indicate that the products are spherical with an average diameter less than 200 nm. Magnetic studies revealed that the saturation magnetization of Co0.4Zn0.6Fe2O4is 78.6 emu/g, higher than the CoFe2O4, which is 69 emu/g, while the coercivity of the Co0.4Zn0.6Fe2O4is 184 Oe , obviously lower than that of CoFe2O4which is 832 Oe. The electromagnetic parameters were measured at 2-18 GHz using HP8722ES vector network analyzer and then the microwave absorption properties were calculated through the transmission line theory. As to the Co0.4Zn0.6Fe2O4, the absorption bandwidth with reflection loss below-10 dB is up to 3GHz, from 10GHz to 13GHz with a thickness of 2 mm. A maximum reflection loss-45.6 dB was found at 12.9 GHz for the CoFe2O4with a thickness of 1.8 mm. As a result, the as-prepared hollow nanospheres show good prospects of being applied in EM wave absorption materials.

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