Magnetic Composite Nanoparticle of Au/γ-Fe2O3 Synthesized by Gamma-Ray Irradiation

Seino, Satoshi; Kinoshita, Takuya; Otome, Yohei; Okitsu, Kenji; Nakagawa, Takashi; Yamamoto, Takao A.

doi:10.1246/cl.2003.690

Cited by 43 publications

(22 citation statements)

References 11 publications

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“…Seino et al 9 reported that gold-supported Fe(III) oxide particles were formed by irradiation of γ-rays to a suspended solution containing Fe(III) oxide and Au(III) ions. The irradiation of electromagnetic waves including γ-rays or ultraviolet (UV) rays is considered to be a useful method for the reduction of Au(III) ions without specific reagents.…”

Section: Introductionmentioning

confidence: 99%

The Effect of UV Irradiation on the Reduction of Au(III) Ions Adsorbed on Manganese Dioxide

et al. 2005

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The effect of UV (ultraviolet) irradiation on the adsorption of Au(III) ions on manganese dioxide and their reduction to Au(0) (gold with 0 valence state) was investigated using XPS (X-ray photoelectron spectroscopy) and 197 Au Mössbauer spectroscopy. The UV irradiation accelerated the adsorption and the reduction. From the fact that the proportion of Au(0) estimated from Au 4f XPS spectra for surface analysis was significantly smaller than that from 197 Au Mössbauer spectra for bulk analysis, we deduced that Au(0) was interpenetrated to the inside of manganese dioxide (into deeper places than about 30 Å) where XPS is impossible to detect. The content of surface hydroxyl groups on manganese dioxide also increased due to the UV irradiation. The relationship between the charge in the content of hydroxyl groups and the interpenetration of Au (0) is discussed.

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Section: Introductionmentioning

confidence: 99%

The Effect of UV Irradiation on the Reduction of Au(III) Ions Adsorbed on Manganese Dioxide

et al. 2005

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“…The mean crystallite size of the sample is determined by using the Debye-Scherrer's formula following standard procedures [45]. The calculated average crystallite size is 26.7 nm, close to the 28 nm average size determined by statistical analysis of the TEM images, indicating that each individual particle is a single crystal.…”

Section: Chemical Characteristic Analysismentioning

confidence: 58%

“…Therefore, another possible reason for the diminution in M s might be the incomplete crystallization of Fe 3 O 4 nanoparticles, which might be due to amorphous impurities undetectable by XRD [48]. [8,31,45]. In those researches; they had dried samples by methods that could prevent magnetite to oxidation [39].…”

Section: Magnetic Properties Analysismentioning

confidence: 99%

Synthesis of magnetite–gold nanoshells by means of the secondary gold resource

2015

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“…So, it can be considered that the exchange coupling happens between ferrites of MFHC and SmFeO 3 . Grain exchange coupling interaction can prevent their directions of magnetic moment from changing along the easy magnetization when two neighboring grains contact directly [12,13]. So, the magnetic moment at the interface changes continuously from one grain direction of easy magnetization to another grain direction of easy magnetization.…”

Section: Resultsmentioning

confidence: 99%

Preparation and thermal analysis kinetics of the core–nanoshell composite materials doped with Sm

Che

Jiang

Wei

et al. 2013

J Therm Anal Calorim

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The core-nanoshell composite materials with magnetic fly-ash hollow cenosphere as core and nano SmFeO 3 as shell were synthesized by high-energy ball milling method. The magnetic fly-ash hollow cenosphere, samarium nitrate, and iron nitrate were used as raw materials. The synthesis and growth kinetics of the composite materials were investigated using the thermogravimetry and differential thermal analysis (TG-DTA) at different heating rates. The results show that the precursor of the composite materials decomposes in three steps. The apparent activation energy of each stage was calculated using the Doyle-Ozawa and Kissinger methods. The reaction order, frequency factor, and rate equations were also determined. The activation energy of the nano crystallite growth is calculated to be 16.12 kJ mol -1 according to kinetics theory of nano crystallite growth. It can be inferred that the crystallite grows primarily by means of an interfacial reaction during the thermal treatment. The magnetic properties and microwave absorbing properties of samples were analyzed by the vibrating sample magnetometer analysis and vector network analyzer. The results indicated that the exchange coupling interaction happens between ferrite of magnetic fly-ash hollow cenosphere and nanosized ferrite coating, which cause outstanding magnetic properties. In the frequency between 1 MHz and 1 GHz, the absorbing effectiveness of the composite absorbers can achieve -32 dB. The magnetic properties of the composite material are better than those of single phase. So it is consistent with requirements of the microwave absorbing material at the low-frequency absorption.

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Magnetic Composite Nanoparticle of Au/γ-Fe2O3 Synthesized by Gamma-Ray Irradiation

Cited by 43 publications

References 11 publications

The Effect of UV Irradiation on the Reduction of Au(III) Ions Adsorbed on Manganese Dioxide

The Effect of UV Irradiation on the Reduction of Au(III) Ions Adsorbed on Manganese Dioxide

Synthesis of magnetite–gold nanoshells by means of the secondary gold resource

Preparation and thermal analysis kinetics of the core–nanoshell composite materials doped with Sm

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