Faculty Profiles - TAKEZAWA Masaaki

Conference Prsentations (Oral, Poster) -

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Kerr効果顕微鏡を用いた磁性材料の磁区構造解析 Invited

竹澤昌晃

第71回応用物理学会春季学術講演会 2024.03 応用物理学会

Microstructure and Magnetic Characterization on Ball-milled Fe-based Nanocrystalline Alloy Sheet

S. Nagata, Y. Horibe, S. Hiramoto, H. Narahara, N. Mori, I. Sasaki, M. Takezawa, Y. Ando, T. Shikayama, S. Mukai, S. Maeda, S. Sakima, T. Ishii, and S. Motozuka

2023 IEEE International Magnetic Conference (Intermag 2023) 2023.05 IEEE

Event date： 2023.05.15 - 2023.05.19 Language：English Country：Japan

To realize the effective utilization of the end material and its application to a soft magnetic composite, Fe-based nanocrystalline alloy sheets were ball-milled, and platelet particles were obtained, in this work. Instrumental analyses revealed that although a micro strain was introduced into the nanocrystalline α-Fe grains in the achieved alloy powder, almost no changes were found in the amorphous part filled among the grains. The ball-milling treatment greatly increased the coercive force of the pulverized nanocrystalline sheet. Although the coercive force of the alloy powder decreased after the heat treatment, the coercive force remained to be approximately 10 times higher than that of the heat-treated alloy sheet without the ball-milling treatment, even after the heat treatment. The magnetic process of the ball-milled and heat treated nanocrystalline alloy powder will be discussed in detail in the conference based on the obtained results and Lorentz transmission electron microscopy.

Effect of Mn Doping on Magnetic Properties, Magnetic Domain Structures, and Microstructures of 2–17 Type Sm–Co Magnets

H. Machida, T. Fujiwara, C. Fujimoto, Y. Kanamori, K. Inoue, and M. Takezawa

2023 IEEE International Magnetic Conference (Intermag 2023) 2023.05 IEEE

Event date： 2023.05.15 - 2023.05.19 Language：English Country：Japan

Magnetic properties, magnetic domain structures, and microstructures of Sm(Fe0.328Cu0.055Zr0.017MnxCobal)7.65 (
�
x = 0.005 and 0.010) were investigated. Even with Mn content increased, magnetic properties did not deteriorate, remanent magnetic flux density,
�
�
B
r

, maximum energy product,
[
�
�
]
�
[BH]
m

, and squareness,
�
�
/
�
�
�
H
k

/H
cj

(
�
�
H
k

is a reverse magnetic field value when magnetization becomes 90% of
�
�
B
r

), exceeded 12 kG, 33.5 MGOe, and 70%, respectively, in both samples. However, a mechanism of magnetic reversal was different; reverse magnetic domains were easy to propagate from grain boundaries in
�
x = 0.005 and grain interior in
�
x = 0.010, respectively. In microstructures, Cu concentration increased in grain boundaries, and cell size enlarged with an increase in Mn content. Because microstructures were formed properly and its size was enlarged, which produce a strong pinning force, and negative effects of doping non-ferromagnetic element Mn were compensated

Magnetic Domain Observation of Milled Nanocrystalline Alloy Powder

M. Takezawa, T. Nagaki, S. Motozuka, I. Sasaki, Y. Ando, H. Narahara, N. Mori, T. Shikayama, S. Mukai, S. Maeda, S. Sakima, and T. Ishii

2023 IEEE International Magnetic Conference (Intermag 2023) 2023.05 IEEE

Event date： 2023.05.15 - 2023.05.19 Language：English Country：Japan

Fe-based nanocrystalline alloys have high magnetic flux density and low loss. So, in this study, the magnetic domain structure of ball-milled magnetic powders of these nanocrystalline alloys was observed using a Kerr effect microscope. The effect of strain removal heat treatment on the magnetic properties of the powder was also investigated by observing and comparing the magnetic domain structure of the milled powder before and after heat treatment during the preparation process of the nanocrystalline milled powder. Our findings showed that the strain removal heat treatment changed the size and shape of the magnetic domains to a simple structure. In addition, the magnetic wall motion was found to occur quickly, resulting in soft magnetic properties.

GSRセンサ用磁性アモルファスワイヤの磁区構造

常藤颯太, 竹澤昌晃, 本蔵義信, 本蔵晋平

第47回日本磁気学会学術講演会 2023.09 日本磁気学会

配向軟磁性粉末シートの磁気特性

竹澤昌晃, 村上康之

2023年度電気・情報関係学会九州支部連合大会 2023.09

無方向性電磁鋼板の板厚と結晶粒径および結晶方位による鉄損の変化

寺嶋康樹, 竹澤昌晃, 森本祐治, 市江毅

電気学会マグネティックス研究会 2023.08 電気学会マグネティックス技術委員会

磁壁移動による無方向性電磁鋼板磁気特性モデル化

開道力, ⽵澤昌晃

電気学会静止器・回転器合同研究会 2023.03

高ダイナミックレンジイメージ技術を用いたNd-Fe-B系焼結磁石の磁区像コントラストの強調

山下塁, 竹澤昌晃

電気学会マグネティックス研究会 2022.12 電気学会マグネティックス技術委員会

Mn添加したSm 2 Co 17 系磁石の磁区観察

井上健次, 竹澤昌晃, 町田浩明, 藤原照彦

電気学会マグネティックス研究会 2022.12 電気学会マグネティックス技術委員会

電磁鋼板における結晶粒界の磁気挙動モデル化の検討

開道力, ⽵澤昌晃

電気学会静止器・回転器合同研究会 2022.09

磁気 Kerr 効果顕微鏡を用いたソフト磁性材料の磁区観察技術

竹澤昌晃

日本金属学会2022年秋期(第171回)講演大会 2022.09 日本金属学会

HDR合成技術を用いた磁気Kerr効果による永久磁石の磁区像の強調

山下塁, 竹澤昌晃

2022年度電気・情報関係学会九州支部連合大会 2022.09

Magnetic domain structure and magnetic properties of soft magnetic materials

M. Takezawa

第46回日本磁気学会学術講演会 2022.09 日本磁気学会

無方向性電磁鋼板における結晶粒界の磁気挙動

開道力, ⽵澤昌晃

電気学会マグネティックス研究会 2022.08 電気学会マグネティックス技術委員会

Nd-Fe-B系焼結磁⽯の加圧・加熱による磁区構造変化と減磁率の評価

⽵澤昌晃, ⽥村紘⼤, 森本祐治, 松本紀久

電気学会マグネティックス研究会 2022.08 電気学会マグネティックス技術委員会

無方向性電磁鋼板の板厚と結晶粒径の変化に伴う磁区構造変化

川久保洋輝, 森本祐治, 竹澤昌晃, 市江毅

令和4年電気学会全国大会 2022.03 電気学会

Nd-Fe-B 系焼結磁石の加熱・加圧の複合効果による磁区構造変化

田村紘大, 江口徳彦, 森本祐治, 竹澤昌晃, 松本紀久

第45回日本磁気学会学術講演会 2021.09 日本磁気学会

Nd添加したSm2Co17系磁石の磁区観察

井上健次, 竹澤昌晃, 町田浩明, 藤原照彦

電気学会マグネティックス研究会電気学会マグネティックス技術委員会

無方向性電磁鋼板の板厚と結晶粒径の変化による鉄損分析

川久保洋輝, 竹澤昌晃, 森本祐治, 市江毅

電気学会マグネティックス研究会電気学会マグネティックス技術委員会

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<TAKEZAWA Masaaki>

Conference Prsentations (Oral, Poster) -