Influence of Oxidation and Size of Iron Nanoparticles on the Saturation Magnetization

Matsuura, Hidenori; Seto, K.; Hu, Yang; Kawano, Kenji; Takahashi, M.; Ogawa, Tomoyuki

doi:10.1109/tmag.2008.2002006

Cited by 10 publications

(4 citation statements)

References 14 publications

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“…[90,91] As metallic iron has much higher magnetization than the iron oxides, oxidation of the embedded Fe 0 nanoparticles should result in a decreased saturation magnetization. [92,93] Therefore, the saturation magnetization of the LSF nanocomposite can be used to estimate the oxidation state of the exsolved nanoparticles. We employed vibrating-sample magnetometry (VSM) to probe the magnetic property of the nanocomposite LSF at different stages of the redox cycling: as-exsolved, mildly oxidized, and heavily oxidized.…”

Section: Tuning Nanocomposite Magnetism Via Redox Switchingmentioning

confidence: 99%

Exsolution Synthesis of Nanocomposite Perovskites with Tunable Electrical and Magnetic Properties

Wang

Syed

Ning

et al. 2021

Adv Funct Materials

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Nanostructured functional oxides play an important role in enabling clean energy technologies and novel memory and processor devices. Using thin‐film La0.6Sr0.4FeO3 (LSF) as a model system, the novel utility of exsolution in fabricating self‐assembled metal oxide nanocomposites with tunable functionalities is shown. Exsolution triggers the formation of metallic iron (Fe0) nanoparticles, Ruddlesden–Popper domains, and nm‐scale percolated Fe‐deficient channels in LSF. Combining multimodal characterization with numerical modeling, the chemical, magnetic, and electrical properties of the exsolution‐synthesized nanocomposite at different stages of Fe0 exsolution as well as during redox cycling are assessed. After exsolution, the electronic conductivity of the nanocomposite LSF increased by more than two orders of magnitude. Based on numerical analysis representing all the constituents, it is expected that this increase in conductivity originates mainly from the Fe‐deficient percolating channels formed during exsolution. Moreover, the exsolved nanocomposite is redox‐active even at moderate temperatures. Such redox capabilities can enable dynamic control of the nanocomposite functionality by tailoring the oxygen non‐stoichiometry. This concept is demonstrated with a continuous modulation of magnetization between 0 and 110 emu cm−3. These findings point out that exsolution may serve as a platform for scalable fabrication of complex metal oxide nanocomposites for electrochemical and electronic applications.

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Section: Tuning Nanocomposite Magnetism Via Redox Switchingmentioning

confidence: 99%

Exsolution Synthesis of Nanocomposite Perovskites with Tunable Electrical and Magnetic Properties

Wang

Syed

Ning

et al. 2021

Adv Funct Materials

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“…Fe NPs were synthesized by our developed thermal decomposition method [3] using an iron carbonyl Fe(CO) 5 , whose total number of injected Fe atoms (hereafter, denoted as n 0 ) was systematically changed from 0.61 × 10 21 (1 mmol) to 4.30 × 10 21 (10 mmol), treated in a glove box under Ar atmosphere with 0.1 ppm -1 ppm of O 2 and H 2 O [3]. 180 deg C of refluxing temperature was fixed and refluxing time was changed from 1 min.…”

Section: Experimental and Analysis Proceduresmentioning

confidence: 99%

“…The NP size and crystalline structure were characterized by the transmission electron microscopy (TEM) and electron diffraction (ED). The saturation magnetization at 5 K of the Fe NPs encapsulated in a quartz tube with epoxy resin cap were measured by a superconducting quantum interference device (SQUID) and with X-ray Fluorescence (XRF) analysis which provides the amount of Fe in the disperse solution [3]. ), respectively.…”

Section: Experimental and Analysis Proceduresmentioning

confidence: 99%

“…In order to obtain a high permeability, high saturation magnetization (M S ) of the NP is required, and pure α phase of Fe is one of the attractive candidates. However, 20-30% of smaller values of the Ms than that of bulk (220 emu/g Fe ) have been obtained for the chemically synthesized Fe NPs using a Fe(CO) 5 as precursor in spite of minimal oxidation during the synthesis [3,4]. Thus, it is necessary to clarify not only the phase of the individual NP but also the relationship between growth process of the phase and Ms.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Nucleation and Growth Dynamics on Saturation Magnetization of Chemically Synthesized Fe Nanoparticles

Ogawa¹,

Seto²,

Hasegawa³

et al. 2011

Journal of Magnetics

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In order to obtain mono-dispersed Fe NPs with high saturation magnetization, quantitative analysis method to investigate the growth dynamics of the Fe NPs synthesized by a conventional thermal decomposition method has been developed. As a result, fast nucleation process promotes formation of ~4 nm of initial nucleus with a non-equilibrium phase, resulting in low saturation magnetization. And slow particle growth with atomic-scaled surface precipitation mode (< 100 atoms/(min·nm 2 )) can form the growth layer on the surface of initial nucleus with high saturation magnetization (~190 emu/g Fe ) as an equilibrium a phase of Fe. Therefore, higher stabilization of small initial nucleus generated just after the injection of Fe(CO) 5 should be one of the key issues to achieve much higher M s of Fe NPs.

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Effect of pH on the magnetic properties and microstructure of Mg0.1Co0.9Fe2O4 prepared by sol–gel self-propagating method

Sun

Suo

et al. 2020

Appl. Phys. A

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Influence of Oxidation and Size of Iron Nanoparticles on the Saturation Magnetization

Cited by 10 publications

References 14 publications

Exsolution Synthesis of Nanocomposite Perovskites with Tunable Electrical and Magnetic Properties

Exsolution Synthesis of Nanocomposite Perovskites with Tunable Electrical and Magnetic Properties

Effect of Nucleation and Growth Dynamics on Saturation Magnetization of Chemically Synthesized Fe Nanoparticles

Effect of pH on the magnetic properties and microstructure of Mg0.1Co0.9Fe2O4 prepared by sol–gel self-propagating method

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