Microwave Absorption Properties of Fe3O4-Graphene Nanohybrids

2017 ◽  
Vol 268 ◽  
pp. 297-301 ◽  
Author(s):  
Yau Thim Ng ◽  
Wei Kong ◽  
Sivanesan Appadu ◽  
Ing Kong
Keyword(s):  
Microwave Absorption ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
In Situ Deposition

Magnetite (Fe3O4)-graphene nanohybrids having three different weight ratios of magnetite to graphene were synthesized by a facile in-situ deposition method. The combination of dielectric properties of graphene and magnetic properties of magnetite makes the nanohybrids an ideal choice of material for microwave absorption applications. In regards to that, the electromagnetic properties and microwave absorbing characteristics were investigated in a frequency range of 1-18 GHz. The reflection loss (RL) reaches a minimum of-40.44 dB at 6.84 GHz with a thickness of 7 mm for the sample containing 73 wt·% of Fe3O4. The bandwidth corresponding to the RL below-10 dB is 7.05 GHz. The as-prepared Fe3O4-graphene nanohybrids showed good microwave absorption ability in the low frequency band (C-band) which can be ascribed to improved impedance matching characteristics, enhanced interfacial polarizations as well as the magnetic loss contributions. Moreover, the frequency related to minimum RL could be tuned by varying the weight ratios of magnetite to graphene.

A Comparable Study on the Microwave Absorption Properties of Al/Fe/Co Doped OMC/Paraffin Wax Composites

NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650014 ◽  
Author(s):  
Yanyan Ren ◽  
Hongfeng Li ◽  
Guanglei Wu ◽  
Le Yang ◽  
Chenhui Zheng ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Impedance Matching ◽  
Paraffin Wax ◽  
Frequency Range ◽  
Great Role ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Broadband Absorption ◽  
Ordered Mesoporous ◽  
Co Doped

Al/Fe/Co doped ordered mesoporous carbon (OMC) composites have been synthesized by a facile method, and the influence of dopant on the electromagnetic (EM) and microwave absorption properties was investigated in the frequency range of 2–18[Formula: see text]GHz. Compared with Fe/Co–OMC composites, the Al–OMC nanocomposite played a great role in adjusting values and frequency dependence of complex permittivity, which gives rise to significant improved microwave absorption and reduced thickness of the corresponding paraffin wax composites. Reflection loss (RL) values less than [Formula: see text]5[Formula: see text]dB and [Formula: see text]10[Formula: see text]dB were obtained in the frequency range of 9.2–18[Formula: see text]GHz and 10.7–14.7[Formula: see text]GHz with a single thickness of 2.00[Formula: see text]mm, respectively. Such enhanced EM wave absorption property of the Al–OMC/paraffin wax composite was ascribed to its superior impedance matching characteristic. Thin thickness, broadband absorption microwave absorbers with Al doped OMC nanocomposites were obtained.

Construction and Microwave Absorption Properties of Core@Double-Shell Structured Fe3O4@Polyaniline@MnO2 Nanospheres

NANO ◽  
2020 ◽  
Vol 15 (03) ◽  
pp. 2050032 ◽  
Author(s):  
Wentong Yang ◽  
Xiansen Yang ◽  
Xiang Li ◽  
Md. Zahidul Islam ◽  
Yubing Dong ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
In Situ Polymerization ◽  
Impedance Matching ◽  
Multiple Reflections ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
The Core ◽  
Absorption Performance ◽  
Minimum Reflection Loss

In this paper, we designed a core@double-shell nanostructure to enhance the electromagnetic wave absorption performance of hybrid nanospheres. Herein, the core@double-shell structured Fe3O4@polyaniline@MnO2 nanospheres were successfully prepared by a facile solvothermal process and in situ polymerization methods. The morphology, structure, magnetism and microwave absorption properties were studied. The results reveal that the FPM nanospheres exhibit extraordinary microwave absorbing performance compared to those of either Fe3O4 or Fe3O4@polyaniline nanospheres. The minimum reflection loss of the FPM nanospheres is [Formula: see text]14.7[Formula: see text]dB at 15.76[Formula: see text]GHz with the thickness of 3.5[Formula: see text]mm, and the corresponding effective absorption bandwidth can reach 4.75[Formula: see text]GHz. The perfect EMW absorption of nanospheres can be ascribed to multi-interface polarization, multiple reflections and good impedance matching originated from the core@double-shell nanostructure.

Intense nonlinear dielectric and magnetic resonances of core–shell Ni@graphene composites and their improved microwave absorption properties

2021 ◽  
Vol 9 (14) ◽  
pp. 4910-4920
Author(s):  
Ying Liu ◽  
Xiaoyu Zhang ◽  
Xin Chen ◽  
Yanxia Wu ◽  
Caili Zhang ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Core Shell ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Band Frequency ◽  
Nonlinear Dielectric ◽  
Magnetic Resonances ◽  
Ku Band

Core/shell Ni@graphene composites are prepared by an in situ CVD process using PMMA precursors. The composites exhibit intense nonlinear dielectric and magnetic resonances at Ku-band frequency range, which are benefit to the absorption of microwave.

scholarly journals Effect of Reaction Time on Microwave Absorption Properties of Fe3O4 Hollow Spheres Synthesized via Ostwald Ripening

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2921 ◽  
Author(s):  
Wei Huang ◽  
Yujiang Wang ◽  
Shicheng Wei ◽  
Bo Wang ◽  
Yi Liang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Absorption ◽  
Ostwald Ripening ◽  
Impedance Matching ◽  
Hollow Spheres ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Magnetic Structures ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Hollow magnetic structures have great potential to be used in the microwave absorbing field. Herein, Fe3O4 hollow spheres with different levels of hollowness were synthesized by the hydrothermal method under Ostwald ripening effect. In addition to their microstructures, the microwave absorption properties of such spheres were investigated. The results show that the grain size and hollowness of Fe3O4 hollow spheres both increase as the reaction time increases. With increasing hollowness, the attenuation ability of electromagnetic wave of Fe3O4 spheres increases first and then decreases, finally increases sharply after the spheres break down. Samples with strong attenuation ability can achieve good impedance matching, which it does preferentially as the absorber thickness increases. Fe3O4 hollow spheres show the best microwave absorption performance when the reaction time is 24 h. The minimum reflection loss (RL (min)) can reach −40 dB, while the thickness is only 3.2 mm.

The synergistic effects of carbon coating and micropore structure on the microwave absorption properties of Co/CoO nanoparticles

2016 ◽  
Vol 18 (44) ◽  
pp. 30507-30514 ◽  
Author(s):  
Xiubo Xie ◽  
Yu Pang ◽  
Hiroaki Kikuchi ◽  
Tong Liu
Keyword(s):  
Microwave Absorption ◽  
Vapor Deposition ◽  
Carbon Coating ◽  
Synergistic Effects ◽  
Impedance Matching ◽  
Chemical Vapor ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Micropore Structure ◽  
Coo Nanoparticles

Microporous Co/CoO/C nanoparticles prepared by combining chemical dealloying and chemical vapor deposition methods exhibited high microwave absorption properties due to the synergistic effects of the carbon coating and the micropore structure on the impedance matching of the absorber.

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.

Facile synthesis and enhanced microwave absorption properties of anthracite-based carbon/Ni3Fe/NiO ternary composites

2020 ◽  
Vol 44 (33) ◽  
pp. 13962-13970
Author(s):  
Hengdong Ren ◽  
Jialin Ma ◽  
Jun Zhou ◽  
Xiangfeng Shu ◽  
Zhenying Liu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Microwave Radiation ◽  
Low Frequency ◽  
Microwave Absorber ◽  
Facile Synthesis ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Radiation Method ◽  
Microwave Radiation Method

A low-frequency microwave absorber was synthesized by using a microwave radiation method.

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