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フェライト焼結体及びフェライト複合体の高周波透磁率に関する研究
https://doi.org/10.11501/3119959
https://doi.org/10.11501/3119959663790ea-49bb-4c9d-8a85-dd995f11ba4c
| 名前 / ファイル | ライセンス | アクション |
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diss_otsu2789.pdf (45.9 MB)
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| Item type | デフォルトアイテムタイプ_（フル）(1) | |||||||||
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| 公開日 | 2023-03-18 | |||||||||
| タイトル | ||||||||||
| タイトル | Study on High-Frequency Permeability in Ferrite Ceramics and Ferrite Composite Materials | |||||||||
| 言語 | en | |||||||||
| タイトル | ||||||||||
| タイトル | フェライト焼結体及びフェライト複合体の高周波透磁率に関する研究 | |||||||||
| 言語 | ja | |||||||||
| 作成者 |
中村, 龍哉
× 中村, 龍哉
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| アクセス権 | ||||||||||
| アクセス権 | open access | |||||||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||||||
| 権利情報 | ||||||||||
| 権利情報 | Copyright(c) by Author | |||||||||
| 主題 | ||||||||||
| 主題Scheme | NDC | |||||||||
| 主題 | 420 | |||||||||
| 内容記述 | ||||||||||
| 内容記述 | The complex permeability spectra of Ni-Zn sintered ferrite and the ferrite composite materials were studied. The complex permeability spectra in the ferrite composite materials depend not on the ferrite particle size but on the volume loading of the ferrite particles. The real part of the complex permeability in low-frequency region decreases as the ferrite volume loading is reduced. The shoulder frequency of the real permeability shifts toward higher frequency with a decrease in the ferrite volume loading, hence the real permeability in high-frequency region does not always decrease with a decrease in the ferrite volume loading : it becomes larger in the ferrite composite materials than in the sintered ferrite. The imaginary part of the complex permeability in low-frequency region also decreases as the ferrite volume loading is reduced. The peak frequency of the imaginary part also shifts toward higher frequency with a decrease in the ferrite volume loading. These experimental facts cannot be expected using the semi-empirical logarithmic law. In order to establish the physical picture on the complex permeability variation, we separate the complex permeability spectra into two contributions : the spin rotational and the domain wall motion components, using the numerical fitting called the inverse cole-cole technique. First, in the sintered ferrite, the domain wall component, the frequency dependence of which is resonance-like, contributes the complex permeability only below 100MHz region. The spin rotational permeability, the frequency dependence of which is relaxation-type, remains even at higher frequency such as 1GHz region. Next, from the experimental results on the ferrite composite materials, the spin permeability strongly depends on the ferrite loading : the static spin susceptibility decreases and the spin resonance frequency shifts toward higher frequency when the ferrite loading is reduced. The domain wall component depends not only on the ferrite loading and but also on the ferrite grain size : the static susceptibility of the domain wall motion decreases and the domain wall resonance frequency shifts toward higher frequency, as the ferrite loading is decreased. While, in low frequency region, the permeability of the ferrite composite materials is lower than that of the sintered ferrite, the permeability of the ferrite composite materials is greater than that of the sintered ferrite at high frequency such as 100MHz region. These features can be explained by the magnetic circuit model calculation. In the model calculation, the parameters, such as static susceptibilities and resonance frequencies, are transformed using the gap parameter, which is a simple index for the averaged structure of the composite materials. In other word, we can estimate the complex permeability spectra for the ferrite composite materials using the magnetic circuit model combined with the spin rotation and the domain wall motion formulations. The magnetic circuit model provides changes in the magnetic connection with the ferrite loading. The introduction of the magnetic inert component causes not only the magnetic dilution but also a cut-off of the magnetic circuit in the materials. Thus, the permeability becomes lower than that expected from the semi-empirical logarithmic law. The feature is attributed to the demagnetizing field generated by the magnetic poles on the interface of the ferrite particle. Simultaneously, the addition of the demagnetizing field on the magnetocrystalline anisotropy field leads to a shift of the resonance frequency toward higher frequency. Additionally, using this model calculation, we obtain the extended Snoek's law for the composite materials, and we can explain the temperature variation of the complex permeability in the ferrite composite materials. Furthermore, this magnetic circuit model can be applied to other phenomena such as the complex permeability variation in low-temperature sintered Ni-Zn-Cu ferrite ceramics and the electromagnetic properties and power losses in Mn-Zn ferrite sintered ceramics. This model calculation is thought to be a useful tool for the development in many high-frequency electromagnetic devices through the evaluation of the complex permeability in the materials. | |||||||||
| 言語 | en | |||||||||
| 内容記述 | ||||||||||
| 内容記述タイプ | TableOfContents | |||||||||
| 内容記述 | Contents Abstract / p1 Acknowledgments / p4 1.Introduction / p5 2.Crystal structure and magnetic properties of spinel ferrite / p8 2.1 Crystal structure / p8 2.2 Magnetic properties / p9 3.Synthesis technique / p14 3.1 Solid state reaction / p14 3.2 Hydrothermal precipitation / p17 4.Frequency dispersion of complex permeability / p20 4.1 Spin rotational permeability / p22 4.2 Domain wall motion contribution / p24 4.3 Inverse cole-cole plot technique / p26 5.Permeability dispersion of Ni-Zn ferrite composite materials / p29 5.1 Complex permeability spectra / p31 5.2 Magnetic circuit model / p33 5.3 Extended Snoek's law / p36 5.4 Temperature variation of permeability spectra / p39 6.Complex permeability in low-temperature sintered Ni-Zn-Cu ferrite / p43 6.1 Sintering ability and permeability / p46 6.2 Permeability variation / p47 7.Electromagnetic properties and power loss in Mn-Zn ferrite ceramics / p50 7.1 Microstructure and electromagnetic properties / p52 7.2 Power loss / p56 8.Concluding remarks / p58 References / p60 | |||||||||
| 言語 | ||||||||||
| 言語 | eng | |||||||||
| 資源タイプ | ||||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_db06 | |||||||||
| 資源タイプ | doctoral thesis | |||||||||
| 出版タイプ | ||||||||||
| 出版タイプ | NA | |||||||||
| 出版タイプResource | http://purl.org/coar/version/c_be7fb7dd8ff6fe43 | |||||||||
| ID登録 | ||||||||||
| ID登録 | 10.11501/3119959 | |||||||||
| ID登録タイプ | JaLC | |||||||||
| 開始ページ | ||||||||||
| 開始ページ | 1 | |||||||||
| 書誌情報 |
p. 1 |
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| 学位授与番号 | ||||||||||
| 学位授与番号 | 乙第2789号 | |||||||||
| 学位名 | ||||||||||
| 言語 | ja | |||||||||
| 学位名 | 博士(理学) | |||||||||
| 学位名 | ||||||||||
| 言語 | en | |||||||||
| 学位名 | Physical Science | |||||||||
| 学位授与年月日 | ||||||||||
| 学位授与年月日 | 1996-01-22 | |||||||||
| 学位授与機関 | ||||||||||
| 学位授与機関識別子Scheme | kakenhi | |||||||||
| 学位授与機関識別子 | 15401 | |||||||||
| 言語 | ja | |||||||||
| 学位授与機関名 | 広島大学 | |||||||||
| 学位授与機関 | ||||||||||
| 言語 | en | |||||||||
| 学位授与機関名 | Hiroshima University | |||||||||
| 旧ID | 31881 | |||||||||
