TAKEZAWA Masaaki

写真a

Title

Professor

Laboratory

1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi, Fukuoka

Research Fields, Keywords

Magnetic domain observation,Permanent magnet,Power electric magnetic material,micro fabrication of magnetic material

E-mail

E-mail address

Phone

+81-93-884-3236

Fax

+81-93-884-3236

Undergraduate Education 【 display / non-display

  • 1994.03   Tohoku University   Faculty of Engineering   Department of Electrical Engineering   Graduated   JAPAN

Post Graduate Education 【 display / non-display

  • 1999.03  Tohoku University  Graduate School, Division of Engineering  Department of Electrical and Communication Engineering  Doctoral Program  Completed  JAPAN

Degree 【 display / non-display

  • Tohoku University -  Doctor of Engineering  1999.03

Biography in Kyutech 【 display / non-display

  • 2019.04
    -
    Now

    Kyushu Institute of TechnologyFaculty of Engineering   Department of Electrical Engineering and Electronics   Professor  

  • 2018.04
    -
    2020.03

    Kyushu Institute of TechnologyOrganization for Promotion of Research and Innovation  

  • 2016.05
    -
    2019.03

    Kyushu Institute of TechnologyFaculty of Engineering   Department of Applied Science for Integrated System Engineering   Professor  

Biography before Kyutech 【 display / non-display

  • 1999.04
    -
    1999.11

    Tohoku University, Research Institute of Electrical Communication   Research Assistant   JAPAN

Academic Society Memberships 【 display / non-display

  • 2013.06
    -
    2018.09
     

    JSPS 147th Committee on Amorphous and Nano-Crystalline Materials  JAPAN

  • 2011.10
    -
    Now
     

    IEEE Magnetics Society  UNITED STATES

  • 2008.04
    -
    Now
     

    Japan Society of Powder and Powder Metallurgy  JAPAN

  • 2008.04
    -
    Now
     

    The Japan Institute of Metals  JAPAN

  • 2004.04
    -
    Now
     

    The Institute of Electrical and Engineers of Japan  JAPAN

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Specialized Field (scientific research fund) 【 display / non-display

  • electric device, electric equipment

 

Research Career 【 display / non-display

  • Sturdy of magnetization reversal mechanism of Nd-Fe-B magnet by using Kerr microscope

    Kerr effect  

    Project Year: 2014.04  -  Now 

  • Development of measurement system of magnetic properties of permanent magnet under stress

    permanent magnet, stress, magnetic domain  

    Project Year: 2012.10  -  Now 

  • magnetic characteristics of Si-Fe electrical sheets

    electrical steel sheet, magnetic domain wall pinning, iron loss  

    Project Year: 2009.04  -  Now 

  • High-speed & high-resolution magnetic domain observation of thermal assisted magnetic reversal with Kerr microscope using UV light

    high resolution magnetic domain observation  

    Project Year: 2011.04  -  2014.03 

  • Observation of high resolution magnetic domain structure and magnetization process of hard magnetic materials

    Nd-Fe-B magnet, Kerr effect microscope  

    Project Year: 2007.04  -  2012.03 

Publications (Article) 【 display / non-display

  • Magnetic properties and microstructures of high heat-resistance Sm-Co magnets with high Fe and low Zr content

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

    AIP Advances    9 ( 12 )   2019.12  [Refereed]

     View Summary

    © 2019 Author(s). The magnetic properties and microstructures of 2-17 type Sm-Co magnets with high Fe and low Zr content were investigated. The developed magnet achieved maximum energy product, [BH]m of 34.5 MGOe, intrinsic coercivity, Hcj of 21.3 kOe and squareness of 73.3% at 25 °C. Temperature coefficients of remanent magnetic flux density, Br and Hcj were 0.034%/K and 0.28%/K respectively, which values were almost as same as the conventional Sm-Co magnets. Moreover, the developed magnets had high magnetization orientation. For XRD, it was found that Zr was preferentially substituted by Co-Co pair, this made interaction between Co and Co stronger, so that heat resistance was maintained. Magnetic domain structures were observed with a Kerr effect microscope, and then it was observed that the developed magnet had strong pinning force. In the microstructures, the developed magnet had 200∼500 nm cell size with Fe and Cu separated clearly. This led to large gap of domain wall energy which produces strong pinning force. Because the developed magnet had high magnetization orientation and large gap of domain wall energy, we achieved high magnetic properties and high heat resistance on the developed magnet.

    DOI Scopus

  • Magnetic Domain Structures and Magnetic Properties of Lightly Nd-Doped Sm-Co Magnets with High Squareness and High Heat Resistance

      55 ( 2 )   2019.02  [Refereed]

     View Summary

    © 1965-2012 IEEE. The relationship between magnetic domain structures and magnetic properties of Nd-doped Sm(Fe, Cu, Zr, Co)7.5 was investigated. In the preparation process, slow cooling between sintering and solution treatment was employed to promote homogenization of microstructures. The developed magnet achieved a maximum energy product, [BH]m, of 33.8 MGOe and coercivity, Hcb, of 11.2 kOe at 25 °C, respectively. Moreover, B-H line at 150 °C was linear, which means that irreversible demagnetization does not occur even at 150 °C. Temperature coefficients of remanent magnetic flux density, Br, and intrinsic coercivity, Hcj, were 0.035%/K and 0.24%/K, respectively, as usual the conventional Sm-Co magnet. Magnetic domain structures were observed with a Kerr effect microscope with a magnetic field applied from 0 to-20 kOe, and then reverse magnetic domains were generated evenly from grain boundaries. Microstructures referred to as 'cell structures' were observed with a scanning transmission electron microscope. Fe and Cu were separated to 2-17 and 1-5 phases, respectively. Moreover, without producing impurity phases, Nd showed the same composition behavior with Sm in a cell structure.

    DOI Scopus

  • 研究調査委員会 レポート:ナノスケール磁性体の構造・組織解析と創製調査専門委員会

    竹澤 昌晃

    電気学会論文誌. A  ( 一般社団法人 電気学会 )  139 ( 10 ) NL10_5 - NL10_5   2019.01

    DOI CiNii

  • Change in Magnetic Domain Structure of Nd-Fe-B Sintered Magnets by Compressive Stress

      203 ( 1 ) 9 - 17   2018.04  [Refereed]

     View Summary

    © 2017 Wiley Periodicals, Inc. To clarify the relationship between compressive stresses and demagnetization of Nd-Fe-B sintered magnets, we have examined the change in domain configuration by compressive stresses using a Kerr microscope. The magnetic domains of five kinds of Nd-Fe-B sintered magnets have been observed. The magnets have a coercivity of 0.8 MA/m to 1.4 MA/m and residual magnetic flux density of 1.3 T to 1.5 T. Irreversible demagnetization of Nd-Fe-B magnets with a low coercivity of 0.875 MA/m and high residual magnetic flux density of 1.41 T to 1.47 T have occurred from applying a compressive stress of 100 MPa. The compression-affected area is approximately 0.14%. The stress more than 50 MPa is needed to demagnetize Nd-Fe-B magnets. The amount of irreversible demagnetization depends upon the intensity of the compressive stress as well as the residual magnetic flux and coercive force of the magnets.

    DOI Scopus

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Publications (Books) 【 display / non-display

  • 次世代永久磁石の開発最前線(共著)

    監修:尾崎 公洋, 杉本 諭(執筆者50名) ( Joint Work )

    エヌ・ティー・エス  2019.02 ISBN: 978-4-8604-3586-8

  • 磁性材料・部品の最新開発事例と応用技術(共著)

    編集:技術情報協会 (執筆者67名) ( Joint Work )

    技術情報協会  2018.03 ISBN: 978-4-8610-4705-3

  • 磁気便覧(共著)

    編集:(公)日本磁気学会(執筆者124名) ( Joint Work )

    丸善出版  2016.01 ISBN: 978-4-621-30014-5

  • Progress of Fundamentals and Developments of Novel Nd-Fe-based Permanent Magnets Free from Dy "jointly worked"

    Supervisor: K. Hono, S. Hirasawa ( Joint Work )

    CMC books  2015.06 ISBN: 978-4-7813-1072-5

  • Magnetics -Fundamentals and Applications- (Revised Edition) "jointly worked"

    IEEJ Technical Committee of Magnetics ( Joint Work )

    CORONA PUBLISHING CO. LTD.  2013.10 ISBN: 978-4-339-00856-2

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Conference Prsentations (Oral, Poster) 【 display / non-display

  • Kerr効果顕微鏡で観察した磁性体の磁区構造と結晶組織の比較

    竹澤 昌晃

    令和2年 電気学会全国大会  (東京電機大学)  2020.03  -  2020.03 

  • 磁区観察を用いたNd添加Sm-Co系磁石の減磁過程の検討

    坂倉 健治, 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  (東京)  2019.12  -  2019.12  電気学会マグネティックス技術委員会

  • フラックスゲート磁気センサの小型・高感度化に向けた磁性アモルファスワイヤの作製.

    向野 伸, 竹澤 昌晃, 森本 祐治, 宮田 大史

    電気学会マグネティックス研究会  (神奈川 慶應大学究所)  2019.12  -  2019.12  電気学会マグネティックス技術委員会

  • Magnetic properties and microstructures of high heatresistance Sm-Co magnets with high Fe and low Zr content

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

    64th Annual Conference on Magnetism and Magnetic Materials  (Las Vegas)  2019.11  -  2019.11 

  • Analysis of Magnetization Process of Magnetic Materials by In-situ Magnetic Domain Observation with a Kerr Microscope

    M. Takezawa  [Invited]

    12th International Conference on Ferrites (ICF12)  (Boston)  2019.10  -  2019.11 

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Industrial Property 【 display / non-display

  • Rear-earth Co-based permanent magnets

    Industrial Property No 特願2017-544376  Unexpectedly No WO2017/061126  Patent No 特6549720  JAPAN

    M. Takezawa, T. Fujiwara, H. Machida, H. Yoshikawa

Lectures 【 display / non-display

  • In-situ Magnetic Domain Observation of Nd-Fe-B Permanent Magnet with a Kerr Microscope

    the 14th International Union of Materials Research Societies- International Conference on Advanced Materials (IUMRS-ICAM2015) ( Jeju, Korea )  2015.10.29 

  • Analysis of Demagnetization Process of Nd-Fe-B Permanent Magnets by Domain Observation Using Kerr Microscope

    2012 ENERGY MATERIALS NANOTECHNOLOGY (EMN FALL) ( Las Vegas, USA )  2012.11.29  ENERGY MATERIALS NANOTECHNOLOGY

  • Magnetic Domain Observation of Nd-Fe-B Permanent Magnets with A High-Resolution Kerr Microscope Using Ultraviolet Light

    2012 Collaborative Conference on Materials Research (CCMR) ( Seoul, South Korea )  2012.06.26  Collaborative Conference on Materials Research (CCMR)

Grants-in-Aid for Scientific Research 【 display / non-display

  • Observation of high-speed magnetic reversal of nano-sized-dots with high resolution Kerr microscope using UV light

    Grant-in-Aid for Young Scientists(B)

    Project Year:  2009.04  -  2011.03

    Project Number:  21760261

  • High speed dynamic domain observation and micro magnetic devices

    Grant-in-Aid for Young Scientists(B)

    Project Year:  2006.04  -  2008.03

    Project Number:  18760255

  • Micro fabrication with high aspect ratio of magnetic material and magnetic micro pump for medical application

    Grant-in-Aid for Scientific Research(B)

    Project Year:  2005.04  -  2007.03

    Project Number:  17360143

  • Dynamic domain observation and high speed reversal control of micro-fabricated magnetic material

    Grant-in-Aid for Young Scientists(B)

    Project Year:  2004.04  -  2006.03

    Project Number:  16760274

  • Thick permanet magnet and medical micro machin by micro fabrication due to anodization

    Grant-in-Aid for Scientific Research(B)

    Project Year:  2002.04  -  2005.03

    Project Number:  14350168

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Contracts 【 display / non-display

  • Magnetic domain observation of amorphous wire for high sensitivity magnetic sensor

    Other joint research

    Project Year:  2009.11  -  2009.11

  • Analysis of MI sensor in a GHz band

    Other joint research

    Project Year:  1999.04  -  2001.03

Other External Funds 【 display / non-display

  • Soft ferrite film depsition with PLD method for micro L element

    Project Year:  2001.09  -  2002.03

 

Activities of Academic societies and Committees 【 display / non-display

  • 2017.06
    -
    2019.05

    The Magnetics Society of Japan   editorial committee,paper committee

  • 2016.07
    -
    2019.06

    The Institute of Electrical and Engineers of Japan   chairperson of committee

  • 2016.01
    -
    2016.12

    The Institute of Electrical and Engineers of Japan  

  • 2014.04
    -
    2017.03

    The Institute of Electrical and Engineers of Japan   committee

  • 2014.01
    -
    2016.12

    The Institute of Electrical and Engineers of Japan   committee

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