Challenge of ultra high frequency limit of permeability for magnetic nanoparticle assembly with organic polymer—Application of superparamagnetism

Hasegawa, D.; Hu, Yang; Ogawa, Tomoyuki; Takahashi, M.

doi:10.1016/j.jmmm.2008.11.041

Cited by 55 publications

(17 citation statements)

References 4 publications

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“…The calculated magnetic phase diagram against frequency for nanoparticle assembly by Haesegawa et al demonstrates that the transition from superparamagnetic state to no response state is strongly dependent upon the ratio of the effectively thermal field of H t = k B T / V P μ 0 M S to effectively magnetic anisotropy field H K 27. In the case of H t < H K , with increasing frequency, nanoparticle assembly undergoes from superparamagnetic state into no response state through ferromagnetic state.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of H t < H K , with increasing frequency, nanoparticle assembly undergoes from superparamagnetic state into no response state through ferromagnetic state. In this case, f b can be written as27, where α is the Gilbert damping constant.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of our samples, however, , nanoparticle assembly undergoes from superparamagnetic state to no response state directly, and f b can be written as27, Eq. (4) suggests that the f b can be interpreted as a resonance frequency originating from the Gilbert damping under thermal field.…”

Section: Resultsmentioning

confidence: 99%

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Exceeding natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation

Song

Liu

et al. 2013

Sci Rep

104

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Magnetic nanoparticles have attracted much research interest in the past decades due to their potential applications in microwave devices. Here, we adopted a novel technique to tune cut-off frequency exceeding the natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation. We observed that the cut-off frequency can be enhanced from 5.3 GHz for Fe3O4 to 6.9 GHz forFe3O4@SiO2 core-shell structure superparamagnetic nanoparticles, which are much higher than the natural resonance frequency of 1.3 GHz for Fe3O4 bulk material. This finding not only provides us a new approach to enhance the resonance frequency beyond the Snoek's limit, but also extend the application for superparamagnetic nanoparticles to microwave devices.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Exceeding natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation

Song

Liu

et al. 2013

Sci Rep

104

View full text Add to dashboard Cite

show abstract

“…Magnetic nanoparticles have attracted much attention due to their potential for various technological applications. 1,2 For such applications, magnetic dynamics of nanoparticle assemblies is as important as, or more important than, that of single particle. In a very dilute particle system with negligibly weak interparticle interaction, magnetic nanoparticles exhibit superparamagnetism in which the magnetic behavior of nanoparticle assembly is governed by the magnetic anisotropy of individual particles.…”

mentioning

confidence: 99%

Spin-glasslike behavior of magnetic ordered state originating from strong interparticle magnetostatic interaction in α-Fe nanoparticle agglomerate

Hiroi

Kura

Ogawa

et al. 2011

Applied Physics Letters

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“…F e NANOPARTICLES (NPs) assemblies have attracted great attention for being excellent soft magnetic material with high saturation magnetization and high permeability, which results from strong magnetostatic dipole interaction and/or direct exchange interaction between Fe NPs [1]. For example, Kura et al reported that Fe NPs assembly had superior high-frequency properties [2].…”

Section: Introductionmentioning

confidence: 99%

Direct Synthesis of Single Crystalline $\alpha$-Fe Nanoparticles With High Saturation Magnetization by Mixed Surfactant

et al. 2012

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Magnetic nanoparticles (NPs) have attracted attention for their potential use in electronic devices and nano-bioengineering applications. Fe NPs made by thermal decomposition from an Fe(CO)x-Oleylamine (OlAm) reacted precursor show high saturation magnetization ( 140 emu/g at 300 K). However, the never reaches to the bulk value (218 emu/g at 300 K) of iron due to the unique crystalline structure of the Fe NPs. Fe NPs coated with OlAm (OlAm-Fe NP) have an expanded (b.c.c.) structure and ultra-fine grains. In this paper, we focus on the adsorption ability of the surfactant to improve via control of phase and grain size. Fe NPs with high saturation magnetization were synthesized by thermal decomposition of Fe(CO) with some surfactants that had weak absorption ability, such as tribenzylamine, trioctylamine, and their mixture. Slow decomposition rate of Fe(CO) and large grain size were obtained by applying surfactants with weak adsorption ability. Especially, Fe NPs that were synthesized by mixed surfactants (mixed surfactant-Fe NPs) have polygonal shape with 6.7 nm in diameter. HRTEM and XRD results suggest that mixed surfactant-Fe NPs are single crystallines of -Fe.of mixed surfactant-Fe NPs is 194 and 183 emu/g at 5 K and 300 K, respectively. These results strongly indicate that single crystallization of -Fe enhances the of Fe NPs and also suggest that optimization of the surfactant adsorption ability is indispensable to promote the single crystallization of Fe NPs.

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Challenge of ultra high frequency limit of permeability for magnetic nanoparticle assembly with organic polymer—Application of superparamagnetism

Cited by 55 publications

References 4 publications

Exceeding natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation

Exceeding natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation

Spin-glasslike behavior of magnetic ordered state originating from strong interparticle magnetostatic interaction in α-Fe nanoparticle agglomerate

Direct Synthesis of Single Crystalline $\alpha$-Fe Nanoparticles With High Saturation Magnetization by Mixed Surfactant

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