Magnetic vortex core-shell Fe3O4@C nanorings with enhanced microwave absorption performance

Wang, Xiao; Pan, Fei; Xiang, Zhen; Zeng, Qingwen; Pei, Ke; Che, Renchao; Lü, Wei

doi:10.1016/j.carbon.2019.10.030

Cited by 328 publications

(60 citation statements)

References 72 publications

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“…In general, the magnetic property affects its magnetic loss behavior, which is associated with following equations

μ' = 1 + (M / H) \cos σ

μ ″ = (M / H) \sin σ

where M is magnetization, H represents the magnetic field, σ means the magnetic lag angle under an external magnetic field. [ 10 ] Therefore, S1 has a higher magnetic loss than other samples. In addition, the coercivity (

H_{c}

) for S1, S2, S3 were 0.45, 0.4, 0.5 kOe, respectively.…”

Section: Resultsmentioning

confidence: 99%

Engineering Dielectric Loss of FeCo/Polyvinylpyrrolidone Core‐Shell Nanochains@Graphene Oxide Composites with Excellent Microwave Absorbing Properties

et al. 2020

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FeCo alloy nanoparticles, as a kind of material with high saturation magnetization, have attracted wide attention in electromagnetic (EM) wave research. However, its application as a wave‐absorbing material is limited by its poor magnetic anisotropy and antioxidant properties. Herein, novel FeCo/Polyvinylpyrrolidone core‐shell nanochains@graphene oxide (GO) composites are successfully fabricated with superior microwave‐absorbing properties. The composites perform excellently in absorbing EM wave, with a strong reflection loss (RL) of −40.94 dB at 14.25 GHz, covering from 10.95 to 15.85 GHz (RL < −10 dB) with a matching thickness of 2.0 mm. The superior absorption properties are mainly attributed to the cooperation between amorphous magnetic FeCo nanoparticles and graphene, which contribute to the magnetic and dielectric loss, respectively. Moreover, the FeCo/PVP core‐shell morphology enhances the interfacial relaxation and surface chemical stability of the FeCo nanochains. Thus, this work provides a template for the new‐designed and facile‐synthesized EM wave‐absorbing material.

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“…In general, the magnetic property affects its magnetic loss behavior, which is associated with following equations

μ' = 1 + (M / H) \cos σ

μ ″ = (M / H) \sin σ

H_{c}

) for S1, S2, S3 were 0.45, 0.4, 0.5 kOe, respectively.…”

Section: Resultsmentioning

confidence: 99%

Engineering Dielectric Loss of FeCo/Polyvinylpyrrolidone Core‐Shell Nanochains@Graphene Oxide Composites with Excellent Microwave Absorbing Properties

et al. 2020

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“…TheAnnealing process could effectively relief the stress and minimize the pinning effect, the H c value listed in table 1 was low, so the hyeteresis was low. As for the eddy current loss, it could be calculated by equation (2). The thickness of a specific sample bafore and after heat treatment is almost the same and the proper annealing temperature would not destory the insulating layers which could be seen in figure 5(a).…”

Section: The Effect Of the Annealing Processmentioning

confidence: 99%

“…Soft magnetics composites (SMCs) are promising substitutes for laminate steels in electromagnetic applications such as transformers, generators and motors [1] due to their core-shell structure [2] and unique properties including high magnetic saturation, high magnetic permeability, high resistivity, low core loss, high degree of productivity and three-dimensional (3D) isotropy [3][4][5]. Basically, the SMC cores are produced by traditional powder metallurgy techniques including mixing soft ferromagnetic powders with insulating materials and lubricants, compacting and pressing them to the desired shapes, as well as the subsequent annealing treatment [3,6] to relieve stress.…”

Section: Introductionmentioning

confidence: 99%

Effects of compaction and heat treatment on the soft magnetic properties of iron-based soft magnetic composites

Pan

Peng²,

Qian

et al. 2020

Mater. Res. Express

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Iron-based soft magnetic composites (SMCs) are promising substitutes for laminate steels in electromagnetic applications due to their excellent magnetic properties and productivity. However, the preparation process is a key factor in deciding the magnetic performance of SMCs. In this work, the Fe-based soft magnetic composites with improved soft magnetic properties were achieved by optimizing the compaction and the annealing process. Results showed that the core-shell structure of powders which would directly have an impact on the permeability and the core loss of the SMCs could be affected by the compaction and the annealing process. In addition, the magnetic properties were enhanced by tuning the microstructure. As a result, the optimal magnetic performance of the compact with high permeability and low total core loss was obtained. The real part of the permeability of the soft magnetic composites could reach a maximal value of 336.8 and a rather low core loss of 2.5 W Kg −1 (measured at 50 mT and 5 kHz). Therefore, soft magnetic composites with enhanced magnetic properties were obtained by optimizing the powder metallurgy (PM) process in this study.

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“…Owing to their superior properties, including high permeability, high-frequency stability, 3D isotropy magnetic field, high productivity and, especially, the high electrical resistivity, iron-based soft magnetic composites (SMCs) with a special core-shell structure [3] have attracted broad academic interest and investigations in order to satisfy the requirements of applications in power electronics, transformers and electric motors at medium to high frequency [4,5]. The iron-based SMCs are conventionally prepared by coating insulating materials onto the pure iron matrix to block the path of closed-current loops and the compaction and annealing process [6].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Phosphate-Alumina Iron-Based Core-Shell Soft Magnetic Composites Fabricated by Sol-Gel Method and Ball Milling Method

Pan

Qian

Wang

et al. 2020

Metals

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Novel Fe-based soft magnetic composites (SMCs) with hybrid phosphate-alumina layers were prepared by both sol-gel and ball-milling methods. The effects of the fabrication methods and the addition of Al 2 O 3 particles on the microstructure and the soft magnetic performance of SMCs were studied. The formation of the hybrid phosphate-Al 2 O 3 shell not only leads to the decrease of the total core loss, but also results in the reduction of the permeability and saturation magnetization. However, the degree of decrease caused by the different methods were not identical. The sample with 8% Al 2 O 3 prepared by the sol-gel method showed the best magnetic performance, exhibiting a high-amplitude permeability (µ a ) of 85.14 and a low total core loss (Ps) of 202.3 W/kg at 50 mT and 100 kHz. The hysteresis loss factor and the eddy current loss factor were obtained by loss separation. The results showed that the samples with the same Al 2 O 3 content prepared by different methods exhibited almost the same total core loss. However, the contribution of the hysteresis loss and the eddy current loss showed an obvious difference in behavior because of the change of the particle shapes and the refinement of the particle size during the ball-milling process.

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Magnetic vortex core-shell Fe3O4@C nanorings with enhanced microwave absorption performance

Cited by 328 publications

References 72 publications

Engineering Dielectric Loss of FeCo/Polyvinylpyrrolidone Core‐Shell Nanochains@Graphene Oxide Composites with Excellent Microwave Absorbing Properties

Engineering Dielectric Loss of FeCo/Polyvinylpyrrolidone Core‐Shell Nanochains@Graphene Oxide Composites with Excellent Microwave Absorbing Properties

Effects of compaction and heat treatment on the soft magnetic properties of iron-based soft magnetic composites

Hybrid Phosphate-Alumina Iron-Based Core-Shell Soft Magnetic Composites Fabricated by Sol-Gel Method and Ball Milling Method

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