Effects of size and anisotropy of magnetic nanoparticles associated with dynamics of easy axis for magnetic particle imaging

Satoshi Ota, Yuki Matsugi, Takeru Nakamura, Ryoji Takeda, Yasushi Takemura, Ichiro Kato, Satoshi Nohara, Teruyoshi Sasayama, Takashi Yoshida, Keiji Enpuku

研究成果: ジャーナルへの寄稿記事

1 引用 (Scopus)

抄録

The structure of magnetic nanoparticles affects the signal intensity and resolution of magnetic particle imaging, which is derived from the harmonics caused by the nonlinear response of magnetization. To understand the key effects of particle structures on the magnetization harmonics, the dependence of the harmonics on the size and anisotropy of different structures was investigated. We measured the harmonic signals with respect to different magnetic nanoparticle structures by applying an AC field with a gradient field for magnetic particle imaging, which was compared with the numerically simulated magnetization properties. In addition, the dynamics of the easy axis of magnetic nanoparticles in the liquid state were evaluated. The difference between the harmonics in the solid and liquid states indicates the effective core size and anisotropy due to particle structures such as single-core, chainlike, and multicore particles. In the case of the chainlike structure, the difference between the harmonics in the solid and liquid states was larger than other structures. In the numerical simulations, core diameters and anisotropy constants were considered as the effective values, such as the increase in anisotropy in the chainlike structure due to dipole interaction. The multicore particles showed high harmonics owing to their large effective core diameters. The superparamagnetic regime in the multicore structure despite the large effective core diameter was derived from the small effective anisotropy. The effective core size and the effective anisotropy of each particle structure and their impacts on the harmonic signals were revealed.

元の言語英語
ページ(範囲)311-318
ページ数8
ジャーナルJournal of Magnetism and Magnetic Materials
474
DOI
出版物ステータス出版済み - 3 15 2019

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Anisotropy
Nanoparticles
harmonics
Imaging techniques
nanoparticles
anisotropy
Magnetization
Liquids
magnetization
liquids
solid state
alternating current
Computer simulation
dipoles
gradients
simulation
interactions

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

これを引用

Effects of size and anisotropy of magnetic nanoparticles associated with dynamics of easy axis for magnetic particle imaging. / Ota, Satoshi; Matsugi, Yuki; Nakamura, Takeru; Takeda, Ryoji; Takemura, Yasushi; Kato, Ichiro; Nohara, Satoshi; Sasayama, Teruyoshi; Yoshida, Takashi; Enpuku, Keiji.

:: Journal of Magnetism and Magnetic Materials, 巻 474, 15.03.2019, p. 311-318.

研究成果: ジャーナルへの寄稿記事

Ota, Satoshi ; Matsugi, Yuki ; Nakamura, Takeru ; Takeda, Ryoji ; Takemura, Yasushi ; Kato, Ichiro ; Nohara, Satoshi ; Sasayama, Teruyoshi ; Yoshida, Takashi ; Enpuku, Keiji. / Effects of size and anisotropy of magnetic nanoparticles associated with dynamics of easy axis for magnetic particle imaging. :: Journal of Magnetism and Magnetic Materials. 2019 ; 巻 474. pp. 311-318.
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abstract = "The structure of magnetic nanoparticles affects the signal intensity and resolution of magnetic particle imaging, which is derived from the harmonics caused by the nonlinear response of magnetization. To understand the key effects of particle structures on the magnetization harmonics, the dependence of the harmonics on the size and anisotropy of different structures was investigated. We measured the harmonic signals with respect to different magnetic nanoparticle structures by applying an AC field with a gradient field for magnetic particle imaging, which was compared with the numerically simulated magnetization properties. In addition, the dynamics of the easy axis of magnetic nanoparticles in the liquid state were evaluated. The difference between the harmonics in the solid and liquid states indicates the effective core size and anisotropy due to particle structures such as single-core, chainlike, and multicore particles. In the case of the chainlike structure, the difference between the harmonics in the solid and liquid states was larger than other structures. In the numerical simulations, core diameters and anisotropy constants were considered as the effective values, such as the increase in anisotropy in the chainlike structure due to dipole interaction. The multicore particles showed high harmonics owing to their large effective core diameters. The superparamagnetic regime in the multicore structure despite the large effective core diameter was derived from the small effective anisotropy. The effective core size and the effective anisotropy of each particle structure and their impacts on the harmonic signals were revealed.",
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AU - Kato, Ichiro

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