Enhanced microwave absorption in Ni/polyaniline nanocomposites by dual dielectric relaxations

Dong, Xiaoli; Zhang, Xue Feng; Huang, Hao; Zuo, Fuyin

doi:10.1063/1.2830995

Cited by 313 publications

(189 citation statements)

References 8 publications

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“…For the imaginary part of the permittivity ε″, it can be seen in Fig. 10 (b) that ε″ of the samples increases with the nanospheres is mainly due to natural resonance of the Fe 3 O 4 nanoparticles [31,32]. It is believed that natural resonance results in strong magnetic loss, implying enhanced microwave absorption by the HPAP-Fe 3 O 4 nanospheres as EM energy is converted into heat energy [33].…”

Section: Microwave Absorption Propertiesmentioning

confidence: 99%

Synthesis of hollow poly(aniline-co-pyrrole)–Fe3O4 composite nanospheres and their microwave absorption behavior

et al. 2012

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Hollow poly(aniline-co-pyrrole)-Fe 3 O 4 (HPAP-Fe 3 O 4 ) nanospheres with significant electromagnetic properties were successfully prepared via the oxidative polymerization of a mixture of aniline and pyrrole in the presence of a magnetic fluid, using a non-ionic surfactant as a template.The products were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis and X-ray photoelectron spectroscopy. The electromagnetic (EM) and microwave absorbing properties of the nanocomposites were also investigated. The HPAP-Fe 3 O 4 nanospheres exhibit superparamagnetic properties, and the conductivity increases with Fe 3 O 4 content. The reflection loss evaluation based on the absorbing wall theory at 2 mm thickness shows that the reflection loss is reinforced in the frequency range of 0.5-10 GHz by the presence of Fe 3 O 4 nanoparticles, and the frequency of minimum reflection loss shifts to a higher value with increasing Fe 3 O 4 content. HPAP-Fe 06 exhibits the best microwave absorbing property between 0.5 and 10GHz.

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Section: Microwave Absorption Propertiesmentioning

confidence: 99%

Synthesis of hollow poly(aniline-co-pyrrole)–Fe3O4 composite nanospheres and their microwave absorption behavior

et al. 2012

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“…The resonant frequencies of ε in the current frequency range are 6.0 and 15.8 GHz, respectively. Dong et al reported that the plot of ε' versus ε'' would be a single semicircle, which was usually defined as the Cole-Cole semicircle 26 . It is worthy to note that the composite present a clear segment of two semicircles in Figure 3(c), suggesting the existence of dual dielectric relaxation processes, while each semicircle corresponds to a Debye dipolar relaxation 26 .…”

Section: Resultsmentioning

confidence: 99%

“…Dong et al reported that the plot of ε' versus ε'' would be a single semicircle, which was usually defined as the Cole-Cole semicircle 26 . It is worthy to note that the composite present a clear segment of two semicircles in Figure 3(c), suggesting the existence of dual dielectric relaxation processes, while each semicircle corresponds to a Debye dipolar relaxation 26 . During the activation of an EM-wave, a redistribution process of the charges occurs periodically between the FeNi cores and the SnO shells.…”

Section: Resultsmentioning

confidence: 99%

“…The hysteresis loss is mainly caused by the time lags of the magnetization vector behind the external EM-field vector and is negligible in weak applied field 17 . Because the size of Ni nanocapsules is less than single magnetic domain (55 nm) 26 , the domain-wall displacement that only occurs in multidomain magnetic materials can be excluded. If the magnetic loss results from eddy current loss, the values of µ''(µ') -2 f -1 should be constant when frequency is varied 19 .…”

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confidence: 99%

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Synthesis, Characterization and Electromagnetic Properties of SnO-coated FeNi Alloy Nanocapsules

et al. 2016

Mat. Res.

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SnO-coated FeNi alloy nanocapsules have been synthesized by an arc-discharge method. Highresolution transmission electron microscopy and x-ray photoelectron spectroscopy analysis show that the nanocapsules have a shell/core structure with FeNi alloy nanoparticles as the core and amorphous SnO as the shell. Dielectric relaxation of SnO shell and the interfacial relaxation between SnO shell and FeNi core lead to the dual nonlinear dielectric resonance. The natural resonance in the SnOcoated FeNi nanocapsules shifts to 14.0 GHz. Reflection loss (RL) reaches -46.1 dB at 14.8 GHz for a matching thickness of 1.95 mm, while it exceeds-20 dB over the 13.6 -16.7 GHz range and it exceeds -10 dB in the whole . In addition, the optimal RL values at 5.0-7.6 GHz with the absorbing thickness of 3.4-5.0 mm just exhibit a slight fluctuation.

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“…Among various potential candidates for EM wave absorbers, the one in the form of magnetic nanoparticles core/ dielectric shell-structured nanocapsules, such as Ni/ZnO, FeNi 3 /SiO 2 , Ni/PANI, Ni/C, and Ni/Ni 2 O 3 nanocapsules, has been of particular interest in recent years owing to its tailorable properties in conjunction with smaller sizes and weights [6][7][8][9][10] . An essence of determining the EM wave absorbing properties of the nanocapsules is to obtain a balance between the permeability of the magnetic nanoparticle cores with the permittivity of the dielectric shells 11 .…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Synthesis of Three-dimensional Butterfly-like Ni Architectures as Microwave Absorbers

Sun

Cui

et al. 2015

Mat. Res.

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Three-dimensional butterfly-like Ni architectures were fabricated by a surfactant-assisted hydrothermal method. The Ni architectures, with lengths of about 20 μm and widths of 4-6 μm, were assembled from tens of Ni nanorods with the averaged diameter of about 200 nm. The Ni nanorods were coated by oxide shells. The saturation magnetization of the Ni architectures was found to be 66.2 emu/g. The magnetic loss in the Ni architectures was mainly caused by the natural resonance, while the dielectric relaxation loss was originated from the interfacial relaxation between the oxide shells and the Ni nanorods in addition to the size distribution and morphology of the Ni architectures. Absorbers with a thickness of 2.1 mm exhibited an optimal reflection loss (RL) value of -38.9 dB at 12.8 GHz. RL values exceeding -20 dB in the 8.0-17.8 GHz range were obtained by choosing absorber thicknesses between 1.5 and 3.2 mm. A quarter-wavelength cancellation model was used to explain the observed thickness dependence of RL peak frequency.

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Enhanced microwave absorption in Ni/polyaniline nanocomposites by dual dielectric relaxations

Cited by 313 publications

References 8 publications

Synthesis of hollow poly(aniline-co-pyrrole)–Fe3O4 composite nanospheres and their microwave absorption behavior

Synthesis of hollow poly(aniline-co-pyrrole)–Fe3O4 composite nanospheres and their microwave absorption behavior

Synthesis, Characterization and Electromagnetic Properties of SnO-coated FeNi Alloy Nanocapsules

Hydrothermal Synthesis of Three-dimensional Butterfly-like Ni Architectures as Microwave Absorbers

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