Updated on 2025/08/17

写真a

 
KITAMOTO YOSHITAKA
 
Organization
School of Materials and Chemical Technology Professor
Title
Professor
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Degree

  • Master of Engineering ( Tokyo Institute of Technology )

  • Doctor of Engineering ( Tokyo Institute of Technology )

Research Areas

  • Nanotechnology/Materials / Nanomaterials

Education

  • Tokyo Institute of Technology   Science of Engineering

    - 1988

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    Country: Japan

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  • Tokyo Institute of Technology   School of Engineering   Department of Electrical and Electronic Engineering

    - 1986

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    Country: Japan

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Research History

  • Institute of Science Tokyo   Professor

    2024.10

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    Country:Japan

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  • Tokyo Institute of Technology   Professor

    2013.12 - 2024.9

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    Country:Japan

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  • Tokyo Institute of Technology

    2000.4 - 2013.11

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  • Tokyo Institute of Technology

    1995.7 - 2000.3

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  • (株)レイケム   主任

    1992.8 - 1995.6

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  • 日本ディジタルイクイップメント(株)   研究員

    1988.4 - 1992.7

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Professional Memberships

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Papers

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Books

  • 第5版実験化学講座28-ナノテクノロジーの化学-(分担)

    丸善  2005 

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MISC

  • Carbon-Free Connected Nanoparticle Catalyst for Enhanced Oxygen Reduction Activity and Durability in Polymer Electrolyte Fuel Cells Reviewed

    Hidenori Kuroki, Takanori Tamaki, Masashi Matsumoto, Masazumi Arao, Yohei Takahashi, Hideto Imai, Yoshitaka Kitamoto, Takeo Yamaguchi

    2018.6

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  • The effect of electrolyte concentration on silicon nanoparticles prepared by laser ablation in liquid Reviewed

    Pattarin Chewchinda, Yoshitaka Kitamoto, Hiroshi Funakubo, Michikazu Hara, Osamu Odawara, Hiroyuki Wada

    2015.5

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  • 光音響イメージング用造影剤の作製と評価 Reviewed

    五十嵐 傑, 口丸 高弘, 張 茹芝, 北本 仁孝, 朝日 剛, 近藤 科江, 小田原 修, 和田裕之

    2015.3

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  • 種々の基板に成長したCo/Pd結晶性多層膜の光誘起磁化歳差運動 Reviewed

    高橋 克典, 西沢望, 西林 一彦, 松田 喬, 岩崎 大和, 北本 仁孝, 宗片 比呂夫

    予稿集   p. 09 - 061   2015.3

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  • Initial growth process of a Co layer on a Pd surface Reviewed

    Nozomi Nishizawa, YOSHITAKA KITAMOTO, Hiro MUNEKATA

    Abstracts book   p. 367   2014.11

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  • Fabrication of Langmuir-Blodgett Film of Surgace-Modefied ZnO Prepared by Solution Process Reviewed

    Yuhei Hasuike, Yoshitaka Kitamoto, Masahiko Hara, Osamu Odawara, Hiroyuki Wada

    2014.8

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  • 磁性ナノ粒子集積体の創製とデバイスへの応用 (特集 ナノ粒子創製と応用の最前線)

    北本 仁孝, 渕上 輝顕, 並木 禎尚

    ケミカルエンジニヤリング = Chemical engineering   59 ( 5 )   333 - 338   2014.5

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    Language:Japanese   Publisher:化学工業社  

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  • Detection of photo-induced ferromagnetic resonance in Co/Pd multilayers with oblique incidence angles Reviewed

    Junichi Saeki, Kazuhiro Nishibayashi, Takashi Matsuda, YOSHITAKA KITAMOTO, Hiro MUNEKATA

    p. 10 - 109   2014.3

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  • ポリビニルピロリドンを用いた光感受性物質を含有するシリカ修飾Y2O3:Er,Ybナノ粒子の合成と評価子 Reviewed

    藤井 邦生, 池畑 友裕, 北本 仁孝, 小田原 修, 和田 裕之

    2014

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  • Incidence angle and polarization dependence of photo-induced FMR in Co/Pd multilayers Reviewed

    J. Saeki, K. Nishibayashi, T. Matsuda, Y. Kitamoto, H. Munekata

    2013.12

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  • ポリビニルピロリドンを用いたアップコンバージョンナノ粒子Y2O3:Er,Ybのシリカコーティングとその光学特性 Reviewed

    藤井邦生, 北本仁孝, 原正彦, 小田原修, 和田裕之

    2013.9

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  • Pulsed optical excitation of ordered spin systems in the weak excitation regime Reviewed

    Hiro MUNEKATA, Takashi Matsuda, Kazuhiro Nishibayashi, YOSHITAKA KITAMOTO, Nozomi Nishizawa

    Abstract booklet   p. 6613 - 69   2013.8

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  • Synthesis of silica-coated upconversion nanoparticles Y2O3:Er,Yb by using polyvinylpyrrolidone Reviewed

    Kunio Fujii, Teruaki Fuchigami, Yoshitaka Kitamoto, Masahiko Hara, Osamu Odawara, Hiroyuki Wada

    2013.3

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  • Co/Pd多層膜における磁化の光誘起才差運動の励起光入射角度依存性 Reviewed

    佐伯 潤一, 西林 一彦, 山本 康介, 松田 喬, 北本 仁孝, 宗片 比呂夫

    予稿集   p. 10 - 093   2013.3

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  • Co/Pd多層膜における磁化の弱励起光誘起才差運動 Reviewed

    山本 康介, 松田 喬, 西林 一彦, 北本 仁孝, 宗片 比呂夫

    予稿集   p. 10 - 089   2013.3

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  • Low-power photo-induced precession of magnetization in ultra-thin Co/Pd multilayer films Reviewed

    K. Yamamoto, T. Matsuda, K. Nishibayashi, Y. Kitamoto, H. Munekata

    IEEE Transactions on Magnetics   49 ( 7 )   3155 - 3158   2013

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  • Fabrication of Iron Oxide Network Shell Particles and Their Application for Non-linear Magnetic Sensing

    ( 34 )   71 - 77   2013

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  • Preparation of Y <inf>2</inf> O <inf>3</inf> :Er,Yb nanoparticles by laser ablation in liquid Reviewed

    Takashi Nunokawa, Yuji Onodera, Masahiko Hara, Yoshitaka Kitamoto, Osamu Odawara, Hiroyuki Wada

    Applied Surface Science   261   118 - 122   2012.11

  • Photo-indeed precession of magnetization in [Co/Pd]5 multilayers with various magnetic anisotropy Reviewed

    K. Yamamoto, K. Nishibayashi, T. Matsuda, Y. Kitamoto, H. Munekata

    Abstract booklet   p. 439   2012.10

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  • Silicon Nanoparticles Prepared by Pulsed Laser Ablation in Liquid Reviewed

    Pattarin Chewchinda, Yoshitaka Kitamoto, Osamu Odawara, Hiroyuki Wada

    2012.9

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  • Magnetically-Guided Drug Delivery System using Magnetic Capsules composed of Nanometer-thick Shell

    KITAMOTO Yoshitaka, FUCHIGAMI Teruaki, NAKAGAWA Masaru, NAMIKI Yoshihisa

    2012 ( 70 )   27 - 31   2012.8

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  • 液中レーザーアブレーションによるY3Al5O12:Ceナノ蛍光体の作製 Reviewed

    鶴岡仙之, 片桐隆雄, 笹川崇男, 北本仁孝, 中村一隆, 山崎陽太郎, 小田原修, 山元明, 和田裕之

    電気化学会第79回大会   2012.3

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  • Sr2MgSi2O7:Eu,Dyナノ粒子のシリカ修飾と光学特性の評価 Reviewed

    石崎美佳, 渕上 輝顕, 片桐 隆雄, 北本 仁孝, 笹川 崇男, 山崎 陽太郎, 小田原 修, 和田 裕之

    電気化学会第79回大会   2012.3

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  • 液中レーザーアブレーションによるシリコンナノ粒子の作製と評価 Reviewed

    小林 宏輝, Pattarin Chewchinda, 北本 仁孝, 中村 一隆, 小田原 修, 和田 裕之

    第12回レーザー学会東京支部研究会, 電気学会 光・量子デバイス技術研究会   2012.3

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  • 液中レーザーアブレーション法により作製したY2O3:Er,Ybナノ粒子の光学特性 Reviewed

    小野寺 裕司, 布川 貴史, 北本仁孝, 原 正彦, 山崎 陽太郎, 中村 一隆, 小田原 修, 和田 裕之

    第59回 応用物理学関係連合講演会   2012.3

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  • Optical Properties of Silica-coated Sr2MgSi2O7:Eu,Dy Nanoparticles Prepared by Laser Ablation in Liquid Reviewed

    Mika Ishizaki, Teruaki Fuchigami, Yoshitaka Kitamoto, Osamu Odawara, Hiroyuki Wada

    Photoluminescence in Rare Earths: Photonic Materials and Devices (PRE'12)   2012.3

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  • 熱分解法を用いたY2O3:Er,Ybナノ粒子の合成 Reviewed

    藤井邦生, グバレビッチ アンナ, 北本仁孝, 原正彦, 山崎陽太郎, 小田原修, 和田裕之

    第59回 応用物理学関係連合講演会   2012.3

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  • Preparation of Silicon Nanoparticles by Laser Ablation in Liquid Reviewed

    Pattarin Chewchinda, Hiroki Kobayashi, Yoshitaka Kitamoto, Yohtaro Yamazaki, Osamu Odawara, Hiroyuki Wada

    2012.3

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  • [Co/Pd] 多層膜構造の作製と光励起によるスピンダイナミクスの評価 Reviewed

    山本康介, 西林一彦, 北本仁孝, 宗片比呂夫

    予稿集   p. 10 - 018   2012.3

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  • Preparation and Optical Properties of Rare Earth Doped Y2O3 Nanoparticles Synthesized by Thermal Decomposition with Oleic Acid Reviewed

    N. Takahashi, A. Gubarevich, J. Sakurai, S. Hata, T. Tsuge, Y. Kitamoto, Y. Yamazaki, O. Odawara, H. Wada

    ADVANCED TEXTILE MATERIALS, PTS 1-3   332-334   1974 - 1978   2011

  • 21pPSB-66 Anomalous Magnetic Property at Low Temperature of FePt Nanoparticles Protected by Polymer

    Iwamoto Takashi, Kitamoto Yoshitaka, Toshima Naoki

    Meeting abstracts of the Physical Society of Japan   62 ( 2 )   448 - 448   2007.8

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    Language:Japanese   Publisher:The Physical Society of Japan (JPS)  

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  • Effect of surfactant on syntheses of Fe-Pt nanoparticles

    YAMAMOTO Teruki, KITAMOTO Yoshitaka

    2006 ( 1 )   1 - 4   2006.11

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  • Crystallization process of amorphous CoFeB film in CoFeB/MgO/CoFeB magnetic tunnel junctions

    TAKEUCHI Takashi, GENSEKI Sou, KITAMOTO Yoshitaka, TSUNEKAWA Koji, NAGAMINE Yoshinori, DJAYAPRAWIRA David D., HOSHI Youichi

    2006 ( 1 )   17 - 20   2006.11

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  • Domain Structure and Magnetotransport Properties in (Ga,Mn)As Wires

    KOIZUMI Gaku, KONDO Tsuyoshi, NOMURA Kenta, KITAMOTO Yoshitaka, MUNEKATA Hiro

    2006 ( 1 )   21 - 24   2006.11

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  • Magnetic Properties of L1_0 Fe-Ni-Pt Films for Heat Assisted Magnetic Recording

    KANEKO Masahiko, SUEKI Kengo, KITAMOTO Yoshitaka

    151   33 - 38   2006.11

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  • Fabrication of Fe-C soft magnetic thin films using facing-targets sputtering method

    Yoshitaka Kitamoto, Hiroyuki Tagami, Kyung Ku Choi, Yohtaro Yamazaki

    Proceedings - Electrochemical Society   PV 2004-23   426 - 432   2006

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  • Domain structure and magnetotransport properties in (Ga,Mn)As wires

    G. Koizumi, T. Kondo, K. Nomura, Y. Kitamoto, H. Munekata

    Physica Status Solidi (C) Current Topics in Solid State Physics   3 ( 12 )   4090 - 4093   2006

  • Fabrication of Fe-Co-C thin films using facing targets sputtering method

    Goro Kiyota, Yoshitaka Kitamoto, Yohtaro Yamazaki

    Electrochimica Acta   51 ( 5 )   921 - 923   2005.11

  • Surface treatment of ferromagnetic nanoparticle-assembly by UV irradiation with ozone

    Mu Pei Chen, Kazuya Kuroishi, Yoshitaka Kitamoto

    Electrochimica Acta   51 ( 5 )   860 - 863   2005.11

  • Magnetotransport measurement of (Ga,Mn)As epilayers with low-temperature annealing

    H. Kato, K. Hamaya, Y. Kitamoto, T. Taniyama, H. Munekata

    Electrochimica Acta   51 ( 5 )   1004 - 1007   2005.11

  • Direct synthesis of L1<inf>0</inf> type Fe-Pt nanoparticles using microwave-polyol method

    Rumiko Minami, Yoshitaka Kitamoto, Tsukasa Chikata, Shunsaku Kato

    Electrochimica Acta   51 ( 5 )   864 - 866   2005.11

  • Surface treatment of ferromagnetic nanoparticle-assembly by UV irradiation with ozone

    Mu-Pei Chen, Kazuya Kuroishi, Yoshitaka Kitamoto

    Electrochimica Acta   51 ( 5 )   860 - 863   2005.11

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  • Fabrication of nanoparticle-assembly assisted by fatty-acid molecules

    Kazuya Kuroishi, Mu Pei Chen, Yoshitaka Kitamoto, Takahiro Seki

    Electrochimica Acta   51 ( 5 )   867 - 869   2005.11

  • Fabrication of Fe-Co-C thin films using facing targets sputtering method

    G Kiyota, Y Kitamoto, Y Yamazaki

    ELECTROCHIMICA ACTA   51 ( 5 )   921 - 923   2005.11

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  • Direct synthesis of L1(0) type Fe-Pt nanoparticles using microwave-polyol method

    R Minami, Y Kitamoto, T Chikata, S Kato

    ELECTROCHIMICA ACTA   51 ( 5 )   864 - 866   2005.11

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  • Fabrication of nanoparticle-assembly assisted by fatty-acid molecules

    K Kuroishi, MP Chen, Y Kitamoto, T Seki

    ELECTROCHIMICA ACTA   51 ( 5 )   867 - 869   2005.11

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  • Evaluation of atomic arrangement in Fe-Pt nanoparticles by x-ray diffraction and Mossbauer spectroscopy

    SAKUMA Hiroshi, TANIYAMA Tomoyasu, KITAMOTO Yoshitaka, ISHII Kiyoshi, YAMAZAKI Yohtaro

    2005 ( 50 )   59 - 64   2005.7

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  • CoZrNb/Fe-C discontinuous multilayer films for GHz applications

    KK Choi, T Murase, Y Fujikawa, Y Kitamoto, Y Yamazaki

    NINTH INTERNATIONAL CONFERENCE ON FERRITES (ICF-9)   171 - 176   2005

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    Web of Science

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  • Structure and Magnetic Properties of Partially Ordered Fe-Pt Nanoparticles Synthesized by Chemical Method

    KITAMOTO Yoshitaka, MINAMI Rumiko, CHIKATA Tsukasa, KATO Syunsaku, NISHIO Hiroaki, YAMAMOTO Hiroshi

    IEICE technical report. Magnetic recording   104 ( 408 )   1 - 4   2004.11

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    Language:Japanese   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Partially ordered Fe-Pt nanoparticles are synthesized by a polyol method with microwave irradiation at 250℃. Whereas the ordered Fe-Pt nanoparticles exhibit coercivity of 3.4 kOe and anisotropy field H_k^<Wr>, of 83 kOe at room temperature, an evaluation of anisotropy field distribution reveals that many particles with low anisotropy field are included. Mossbauer spectroscopy shows 60 % of Fe atoms in the partially ordered Fe-Pt nanoparticles are in the L1_0 ordered structure.

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  • 12aPS-26 Synthesis and Magnetic Properties of Co Nanowhiskers

    Iwamoto Takashi, Kitamoto Yoshitaka, Yamazaki Yohtaro, Toshima Naoki

    Meeting abstracts of the Physical Society of Japan   59 ( 2 )   345 - 345   2004.8

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  • 12aPS-34 Spin polarized electron transport across Fe wire/GaAs

    Wada E, Taniyama T., Kitamoto Y.

    Meeting abstracts of the Physical Society of Japan   59 ( 2 )   347 - 347   2004.8

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  • 27aPS-41 Magnetotransport measurements of the annealed (Ga,Mn)As epilayer

    Kato H, Hamaya K, Taniyama T, Kitamoto Y, Munekata H

    Meeting abstracts of the Physical Society of Japan   59 ( 1 )   444 - 444   2004.3

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  • Activation volume and magnetization reversal of assembled-films composed of magnetically isolated Fe-Pt nanoparticles

    M. P. Chen, Y. Kitamoto

    The 49th Annual Conference on Magnetism & Magnetic Materials   2004

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  • Structure and Magnetic Properties of Partially Ordered Fe-Pt Nanoparticles Synthesized by Chemical Method

    KITAMOTO Yoshitaka, MINAMI Rumiko, CHIKATA Tsukasa, KATO Syunsaku, NISHIO Hiroaki, YAMAMOTO Hiroshi

    ITE technical report   28 ( 64 )   1 - 4   2004

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  • (Ga, Mn)As薄膜における[110]一軸磁気異方性とキャリア濃度の関係

    濱屋宏平, 谷山智康, 北本仁孝, 守谷頼, 大岩顕, 宗片比呂夫

    日本物理学会第59回年次大会   2004

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  • 目下話題の磁気記録材料 「化学合成によるFePt規則合金微粒子」

    北本仁孝

    (社)未踏科学技術協会・磁性材料研究会21・第4回講演会   2004

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  • Fe-Ptナノ粒子の構造と磁性

    北本仁孝, 佐久間洋志, 山崎陽太郎, 西尾博明, 山元洋

    (社)粉体粉末冶金協会 平成16年度春季大会   2004

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  • (Ga,Mn)As薄膜におけるアニール効果の磁気伝導評価

    加藤裕明, 浜屋宏平, 谷山智康, 北本仁孝, 宗片比呂夫

    日本物理学会第59回年次大会   2004

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  • カーボンコートしたFe-Ptナノ粒子集積膜の微細構造と磁気特性

    陳穆霈, 黒石和哉, 北本仁孝

    第28回日本応用磁気学会学術講演会概要   2004

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  • (Ga,Mn)As薄膜の交流磁化率と磁気異方性

    濱屋宏平, 谷山智康, 北本仁孝, 宗片比呂夫

    日本物理学会2004年秋季大会   2004

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  • マイクロ波照射ポリオール還元法により合成したFe-Ptナノ粒子の磁気異方性

    南瑠美子, 北本仁孝, 近田司, 加藤俊作

    第28回日本応用磁気学会学術講演会概要   2004

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  • 飽和脂肪酸分子を混合して作製したFe-Ptナノ粒子配列膜

    黒石和哉, 陳穆霈, 北本仁孝, 関隆広

    第28回日本応用磁気学会学術講演会概要   2004

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  • High-Field Torque Measurement of FePt Nanoparticles

    H. Sakuma, H. Nishio, Y. Kitamoto, Y, Yamazaki, H. Yamamoto

    Trans. Magn. Soc. Japan   4 ( 1 )   24 - 27   2004

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    Two methods using torque measurement in magnetic fields of up to 90 kOe were applied to evaluating the magnetocrystalline anisotropy of FePt nanoparticle samples with various order parameters. The maximum anisotropy field in the samples was obtained from the rotational hysteresis loss measurement. It was shown that the maximum anisotropy field monotonically increases with the order parameter. The magnetic anisotropy constant corresponding to the maximum anisotropy field of the sample with an order parameter of 0.96 is 4.4×107erg/cm3. The anisotropy field distribution was also obtained by using Flanders and Shtrikman's method. Thermal relaxation of magnetization was, however, superimposed on the anisotropy field distribution at 300 K.

    DOI: 10.3379/tmjpn2001.4.24

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  • ラングミュア・ブロジェット法によるFe-Ptナノ粒子集積膜の作製

    黒石和哉, 伊藤宏樹, 北本仁孝

    科学技術振興調整費先導的研究等の推進「ナノ界面制御による磁気記録材料の創製」公開シンポジウム   2004

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  • Magnetic Nanoparticles and Their Self-assembly

    Yoshitaka Kitamoto

    AUN/SEED-Net Field-Wise Seminar on NANOMATERIALS-Recent Advances, Perspective and Chanllenges KEYNOTE LECTURE   2004

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  • Fe-Coスパッタ薄膜へのカーボン添加効果

    清田吾朗, 北本仁孝, 山崎陽太郎

    第28回日本応用磁気学会学術講演会概要   2004

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  • Fe-Pt粒子の規則度と磁気異方性

    北本仁孝, 佐久間洋志, 谷山智康, 山崎陽太郎, 西尾博明, 山元洋

    科学技術振興調整費先導的研究等の推進「ナノ界面制御による磁気記録材料の創製」公開シンポジウム   2004

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  • Synthesis of Fe-Pt Ordered Alloy Nanoparticles by Microwave-assisted Polyol Method

    Rumiko Minami, Yoshitaka Kitamoto, Tsukasa Chikata, Shunsaku. Kato

    International Symposium on Microwave Science and Its Application to Related Fields (MICROWAVE 2004)   2004

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  • Annealing-Temperature Dependent Magnetic Behaviorof FePt Nanoparticle-Assemblies Deposited by Langmuir-Blodgett Method

    M. Chen, Y. Kitamoto

    9th Joint MMM/Intermag Conference   2004

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  • Influence of Chemical Conditions in Fabrication of Bi-YIG Precursor on Morphological and Magnto-Optical Response of Its Particulate Film

    C. S. Kuroda, T. Taniyama, Y. Kitamoto, K, Uchida F, Ikazaki Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Mossbauer Study of Atomic Ordering in FePt Nanoparticles

    Y. Kitamoto, H. Sakuma, Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Magnetic confuguration of (Ga,Mn)As wires controlled by hole concentration or temerature

    K. Hamaya, T. Taniyama, Y. Kitamoto, Y. Yamazaki, R. Moriya, A. Oiwa, H. Munekata

    The 10th Physics and Application of Spin-Related Phenomena in Semiconductors   2004

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  • Cation Order Dependent Magntization and Magnetoresistance of Double Perovskite Sr2FeMoO6

    H. Sakuma, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Magnetic Nanoparticles and Their Self-assembly

    Yoshitaka Kitamoto

    AUN/SEED-Net Field-Wise Seminar on NANOMATERIALS-Recent Advances, Perspective and Chanllenges KEYNOTE LECTURE   2004

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  • Synthesis of Fe-Pt Ordered Alloy Nanoparticles by Microwave-assisted Polyol Method

    Rumiko Minami, Yoshitaka Kitamoto, Tsukasa Chikata, Shunsaku. Kato

    International Symposium on Microwave Science and Its Application to Related Fields (MICROWAVE 2004)   2004

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  • Annealing-Temperature Dependent Magnetic Behaviorof FePt Nanoparticle-Assemblies Deposited by Langmuir-Blodgett Method

    M. Chen, Y. Kitamoto

    9th Joint MMM/Intermag Conference   2004

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  • Influence of Chemical Conditions in Fabrication of Bi-YIG Precursor on Morphological and Magnto-Optical Response of Its Particulate Film

    C. S. Kuroda, T. Taniyama, Y. Kitamoto, K, Uchida F, Ikazaki Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Mossbauer Study of Atomic Ordering in FePt Nanoparticles

    Y. Kitamoto, H. Sakuma, Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • CoZrNb/Fe-C Discontinuous Multilayer Films for GHz Applications

    K. Choi, T, Murase, Y. Fujikawa, Y. Kitamoto, Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Cation Order Dependent Magntization and Magnetoresistance of Double Perovskite Sr2FeMoO6

    H. Sakuma, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    9th International Conference on Ferrites   2004

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  • Fabrication of Fe-C soft magnetic thin films by facing-targets sputtering method

    Yoshitaka Kitamoto, Hiroyuki Tagami Kyung-Ku Choi Yohtaro Yamazaki

    5th International Symposium on Electrochemical Micro & Nnano System Technologies   2004

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  • Magnetic confuguration of (Ga,Mn)As wires controlled by hole concentration or temerature

    K. Hamaya, T. Taniyama, Y. Kitamoto, Y. Yamazaki, R. Moriya, A. Oiwa, H. Munekata

    The 10th Physics and Application of Spin-Related Phenomena in Semiconductors   2004

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  • High-Field Torque Measurement of FePt Nanoparticles

    SAKUMA H., NISHIO H., KITAMOTO Y., YAMAZAKI Y., YAMAMOTO H.

    Journal of the Magnetics Society of Japan   4 ( 1 )   24 - 27   2004

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    Two methods using torque measurement in magnetic fields of up to 90 kOe were applied to evaluating the magnetocrystalline anisotropy of FePt nanoparticle samples with various order parameters. The maximum anisotropy field in the samples was obtained from the rotational hysteresis loss measurement. It was shown that the maximum anisotropy field monotonically increases with the order parameter. The magnetic anisotropy constant corresponding to the maximum anisotropy field of the sample with an order parameter of 0.96 is 4.4×107erg/cm3. The anisotropy field distribution was also obtained by using Flanders and Shtrikman's method. Thermal relaxation of magnetization was, however, superimposed on the anisotropy field distribution at 300 K.

    DOI: 10.3379/tmjpn2001.4.24

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  • Control of Magnetic Anisotropy and Magnetotransport in Epitaxial Micropatterned (Ga,Mn)As Wire Structures

    K. Hamaya, R. Moriya, A. Oiwa, T. Taniyama, Y. Kitamoto, H. Munekata

    IEEE Transactions on Magnetics   39 ( 5 )   2785 - 2787   2003.9

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  • Effect of atomic ordering on magnetization decay and activation volume of FePt nanoparticles

    H Sakuma, H Nishio, Y Kitamoto, Y Yamazaki, H Yamamoto

    IEEE TRANSACTIONS ON MAGNETICS   39 ( 5 )   2758 - 2760   2003.9

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  • Magnetoresistance and magnetic anisotropy of (Ga, Mn) As wires

    Hamaya K., Taniyama T., Kitamoto Y., Moriya R., Munakata H.

    Meeting abstracts of the Physical Society of Japan   58 ( 2 )   392 - 392   2003.8

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  • Anomalous hall resistivity due to grain boundary in manganite thin films

    T. Taniyama, K. Hamaya, Y. Kitamoto, Y. Yamazaki

    Journal of Applied Physics   93 ( 10 )   8107 - 8109   2003.5

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    DOI: 10.1063/1.1543865

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  • Anomalous Hall resistivity due to grain boundary in manganite thin films

    T Taniyama, K Hamaya, Y Kitamoto, Y Yamazaki

    JOURNAL OF APPLIED PHYSICS   93 ( 10 )   8107 - 8109   2003.5

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  • Cation order and magnetic properties of double perovskite Sr2FeMoO6

    H Sakuma, T Taniyama, Y Kitamoto, Y Yamazaki

    JOURNAL OF APPLIED PHYSICS   93 ( 5 )   2816 - 2819   2003.3

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  • Asymmetric transport due to spin injection into a Kondo alloy

    T Taniyama, N Fujiwara, Y Kitamoto, Y Yamazaki

    PHYSICAL REVIEW LETTERS   90 ( 1 )   016601_1-4   2003.1

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  • (Ga,Mn)As細線の異方的磁気輸送特性

    濱屋宏平, 守谷頼, 大岩顕, 谷山智康, 北本仁孝, 宗片比呂夫

    第50回応用物理学関係連合講演会   2003

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  • FePt nanoparticle-assembly for magnetic recording media

    Y Kitamoto, H Sakuma, A Jogo, T Taniyama, Y Yamazaki, H Nishio, H Yamamoto

    MAGNETIC MATERIALS, PROCESSES, AND DEVICES VII AND ELECTRODEPOSITION OF ALLOYS, PROCEEDINGS   2002 ( 27 )   483 - 490   2003

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  • FePt微粒子薄膜のLangmuir-Blodgett法による作製

    伊藤宏樹, 黒石和哉, 陳穆霈, 北本仁孝

    粉体粉末冶金協会講演概要集平成15年度秋季大会   2003

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  • 微細加工を用いた(Ga,Mn)Asの磁気構造

    濱屋宏平, 守谷頼, 谷山智康, 北本仁孝, 大岩顕, 宗片比呂夫

    第64回応用物理学会学術講演会   2003

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  • FePtナノ粒子粉末の強磁場トルク測定

    佐久間洋志, 西尾博明, 北本仁孝, 山崎陽太郎, 山元洋

    第27回日本応用磁気学会学術講演概要集   2003

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  • 熱処理温度によるFePt微粒子集積膜の構造及び磁気特性の変化

    陳穆霈, 北本仁孝, 山崎陽太郎

    粉体粉末冶金協会講演概要集平成15年度秋季大会   2003

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  • 高周波用CoZrNb/Fe-C積層膜

    崔京九, 村瀬琢, 藤川佳則, 北本仁孝, 山崎陽太郎

    第27回日本応用磁気学会学術講演概要集   2003

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  • 対向ターゲット式スパッタリング法によるFe-C軟磁性薄膜の作製

    田上裕之, 崔京九, 北本仁孝, 山崎陽太郎

    第27回日本応用磁気学会学術講演概要集   2003

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  • (Ga,Mn)As薄膜における面内磁気抵抗の温度依存性

    濱屋宏平, 守谷頼, 谷山智康, 北本仁孝, 宗片比呂夫

    第27回日本応用磁気学会学術講演概要集   2003

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  • High-frequency Properties of CoZrNb/Fe-C Multilayer Films

    K.-K. Choi, T, Murase T, Yokoshima T. Osaka, Y. Kitamoto, Y. Yamazaki

    Trans. Magn. Soc. Japan   3 ( 2 )   55 - 58   2003

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    High permeability of -500 up to the GHz frequency range was observed in a CoZrNb/Fe-C multilayer film deposited by using a facing-target sputtering apparatus at room temperature. It was found that the Fe-C layer played a key role in increasing the saturation magnetization and the anisotropy field of the multilayer film sufficiently to raise the ferromagnetic resonance frequency beyond 2.0GHz. The multilayer film was soft magnetic when the thickness of the Fe-C layer was 5-50 nm. The Fe-C layer exhibited a columnar growth feature, and the aspect ratio of the column increased with increasing the Fe-C layer thickness. Magnetic anisotropy perpendicular to the film plane appeared in multilayer films with Fe-C layer thicknesses of -80nm and above.

    DOI: 10.3379/tmjpn2001.3.55

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  • Magnetotransport study of temperature dependent magnetic anisotropy in a (Ga,Mn)As epilayer

    K.Hamaya, T.Taniyama, Y.Kitamoto, R.Moriya, H.Munekata

    J.Appl.Phys.   94 ( 12 )   7657 - 7661   2003

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  • Control of Magnetic Features in Epitaxial Micro-Patterned (Ga,Mn)As Wire Structures

    K. HAMAYA, R, MORIYA A, OIWA T, TANIYAMA Y, KITAMOTO, H. MUNEKATA

    IEEE Trans. on Magn.   39 ( 5 )   2785 - 2787   2003

  • Cation Order and Magnetic Properties of Double Perovskite Sr2FeMoO6

    Hiroshi Sakuma, Tomoyasu Taniyama Yoshitaka Kitamoto Yohtaro Yamazaki

    J. Appl. Phys.   93 ( 5 )   2816 - 2819   2003

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  • High-frequency Properties of CoZrNb/Fe-C Multilayer Films

    CHOI K.-K., MURASE T., YOKOSHIMA T., OSAKA T., KITAMOTO Y., YAMAZAKI Y.

    Journal of the Magnetics Society of Japan   3 ( 2 )   55 - 58   2003

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    High permeability of -500 up to the GHz frequency range was observed in a CoZrNb/Fe-C multilayer film deposited by using a facing-target sputtering apparatus at room temperature. It was found that the Fe-C layer played a key role in increasing the saturation magnetization and the anisotropy field of the multilayer film sufficiently to raise the ferromagnetic resonance frequency beyond 2.0GHz. The multilayer film was soft magnetic when the thickness of the Fe-C layer was 5-50 nm. The Fe-C layer exhibited a columnar growth feature, and the aspect ratio of the column increased with increasing the Fe-C layer thickness. Magnetic anisotropy perpendicular to the film plane appeared in multilayer films with Fe-C layer thicknesses of -80nm and above.

    DOI: 10.3379/tmjpn2001.3.55

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  • (Ga,Mn)As薄膜における磁気異方性のアニール効果

    加藤裕明, 濱屋宏平, 守谷頼, 谷山智康, 北本仁孝, 宗片比呂夫

    第27回日本応用磁気学会学術講演会概要集   2003

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  • Open the Gate of the Academic Ivory Tower!!!

    KITAMOTO Yoshitaka

    53 ( 11 )   705 - 705   2002.11

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  • Change in resistance of CuFe wires induced by spin injection

    T Taniyama, N Fujiwara, Y Kitamoto, Y Yamazaki

    IEEE TRANSACTIONS ON MAGNETICS   38 ( 5 )   2872 - 2874   2002.9

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  • Bi-YIG nanoparticle and plastic hybridized magnetooptical material

    TY Kim, T Hirano, Y Kitamoto, T Hasegawa, H Koinuma, Y Yamazaki

    IEEE TRANSACTIONS ON MAGNETICS   38 ( 5 )   3240 - 3242   2002.9

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  • Interlayer coupling in (In,Mn)As/InAs/(In,Mn)As magnetic semiconductor trilayer structures

    S Yanagi, H Munekata, Y Kitamoto, A Oiwa, T Slupinski

    JOURNAL OF APPLIED PHYSICS   91 ( 10 )   7902 - 7904   2002.5

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  • Magneto-optical properties and morphology of particulate film consisting of Bi-YIG coprecipitated particles

    CS Kuroda, T Taniyama, Y Kitamoto, Y Yamazaki

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   241 ( 2-3 )   201 - 206   2002.3

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  • FePt Nanoparticle-assembly for Magnetic Recording Media

    Yoshitaka Kitamoto, Hiroshi Sakuma Arata Jogo Tomoyasu, Taniyama Yohtaro Yamazaki

    Electrochemical Society Meeting/7th International Symposium on Magnetic Materials, Processes and Devices   2002

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  • FePtナノ粒子の作製と磁気特性

    佐久間洋志, 城後新, 谷山智康, 北本仁孝, 山崎陽太郎

    (社〕粉体粉末冶金協会 平成14年度春季大会   2002

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  • 高密度磁気記録媒体用ナノ粒子の合成と集積膜

    佐久間洋志, 城後新, 谷山智康, 北本仁孝, 山崎陽太郎

    電気化学会春季講演会   2002

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  • 界面活性剤を添加して焼成した時のYIG微粒子結晶化への影響

    柿原康男, 高橋亮, 北本仁孝, 山崎陽太郎

    第26回日本応用磁気学会学術講演会   2002

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  • 溶液プロセスにより作製したFePt微粒子の磁気緩和

    佐久間洋志, 城後新, 西尾博明, 北本仁孝, 山崎陽太郎, 山元洋

    第26回日本応用磁気学会学術講演会   2002

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  • 共沈法によるBi-YIG微粒子合成における硫酸アンモニウム添加の効果

    高橋亮, 柿原康男, 北本仁孝, 山崎陽太郎

    (社〕粉体粉末冶金協会 平成14年度秋季大会   2002

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  • CoZrNb/Fe-C積層膜の高周波特性

    崔京九, 村瀬琢, 横島時彦, 逢坂哲弥, 北本仁孝, 山崎陽太郎

    第26回日本応用磁気学会学術講演会   2002

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  • Fabrication and self-assembling of FePt nanoparticles

    SAKUMA Hiroshi, JOGO Arata, TANIYAMA Tomoyasu, KITAMOTO Yoshitaka, YAMAZAKI Yohtaro

    ITE Technical Report   26 ( 38 )   25 - 28   2002

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    Nanoparticles of FePt were fabricated by two types of solution process. One is thermal decomposition and reduction of organometallic compounds in nonpolar solvent; the other is reduction of metal ions in reversed micelles. In either way, monodisperse FePt particles of about 3nm are formed. Self-assembly was observed in case of the particles fabricated by the former method, while in case of the latter method, self-assembly was not observed. The maximum diameter of particles in assembled film increased up to 1Onm by annealing.

    DOI: 10.11485/itetr.26.38.0_25

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  • FePtナノ粒子のウエットプロセスによる合成と集積薄膜

    佐久間洋志, 城後新, 谷山智康, 北本仁孝, 山崎陽太郎

    未来開拓学術研究推進事業「原子界面設計による高密度磁気記録デバイスの研究開発」プロジェクト公開シンポジウム・成果報告会   2002

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  • Magnetic Properties of FePt particles and their assembly-films

    KITAMOTO Yoshitaka, SAKUMA Hiroshi, ITOH Hiroki, YAMAZAKI Yohtaro, NISHIO Hiroaki, YAMAMOTO Hiroshi

    ITE Technical Report   26   29 - 32   2002

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    Nanparticles of FePt were fabricated by two types of solution process. One is thermal decomposition and reduction of organometallic compounds in an organic slovent, and the other is reduction of metl ions in reversed micelles based on an aqueous solutiion process. In either way, mondisperse FePt prticles of about 3nm are fourmed. Self-assembly was observed in case of the particles fabricated by the former method, while in case of the latter method, self-assembly was not observe. The maximum diameter of particles in assembled film increased up to 10nm by annealing. Magnetic evaluation in the from of powder showed that atomic ordering of Fe and Pt in L1_0 structure strongly influenced coercivity and magnetization decay.. It is necessary to improve the accuracy for magnetic measurements of very thin assembly-films since their magnetization is too small.

    DOI: 10.11485/itetr.26.71.0_29

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  • FePt Nanoparticle-assembly for Magnetic Recording Media

    Yoshitaka Kitamoto, Hiroshi Sakuma Arata Jogo Tomoyasu, Taniyama Yohtaro Yamazaki

    Electrochemical Society Meeting/7th International Symposium on Magnetic Materials, Processes and Devices   2002

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  • Crossober of magnetotransport process toward spin-polarized tunneling in manganite thin films

    T.Taniyama, N.Fujiwara, Y.Kitamoto, Y.Yamazaki

    Appl.Phys.Lett.   81 ( 24 )   4562 - 4564   2002

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  • Magnetic Properties of FePt Particles and Their Assembly-films

    Yoshitaka Kitamoto, Hiroshi Sakuma, Hiroki Itoh Yohtaro, Yamazaki, Hiroshi Yamamoto

    7th Asian Symposium on Information Storage Technology   26   29 - 32   2002

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    Nanparticles of FePt were fabricated by two types of solution process. One is thermal decomposition and reduction of organometallic compounds in an organic slovent, and the other is reduction of metl ions in reversed micelles based on an aqueous solutiion process. In either way, mondisperse FePt prticles of about 3nm are fourmed. Self-assembly was observed in case of the particles fabricated by the former method, while in case of the latter method, self-assembly was not observe. The maximum diameter of particles in assembled film increased up to 10nm by annealing. Magnetic evaluation in the from of powder showed that atomic ordering of Fe and Pt in L1_0 structure strongly influenced coercivity and magnetization decay.. It is necessary to improve the accuracy for magnetic measurements of very thin assembly-films since their magnetization is too small.

    DOI: 10.11485/itetr.26.71.0_29

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  • Improvement in magneto-optical properties of Bi-YIG particulate films by reduction in particle size

    CS Kuroda, T Taniyama, Y Kitamoto, Y Yamazaki, T Hirano

    IEEE TRANSACTIONS ON MAGNETICS   37 ( 4 )   2432 - 2434   2001.7

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  • Improving Fine Structure of Co Ferrite Magnetic Thin Film by Ni Addition

    F. Zhang, Y. Kitamoto, M. Abe, M. Naoe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   1073 - 1075   2001

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  • Magnetic and recording characteristics of Co-Ni ferrite recording layers on soft ferrite underlayers

    Fuchun Zhang Nobuhiro Matsushita Masanori Abe, Yoshitaka Kitamoto

    The 8th Joint MMM-Intermag Conference   2001

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  • 強磁性FePtナノ微粒子の逆ミセルによる作製

    城後新, 谷山智康, 北本仁孝, 山崎陽太郎

    第25回日本応用磁気学会学術講演会   2001

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  • Magnetic and Read/write Characteristics of CoNi Ferrite Perpendicular Recording Media with Soft Ferrite Underlayers

    Fuchun Zhang Nobuhiro Matsushita Masanori Abe, Yoshitaka Kitamoto

    International Conference on Materials for Advanced Technologies   2001

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  • フェライトめっき法によるマグネタイト薄膜の微細加工と電気的特性

    栗原淳旨, 谷山智康, 北本仁孝, 山崎陽太郎

    (社〕粉体粉末冶金協会 平成13年度秋季大会   2001

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  • Co/Cu(Fe)接合細線におけるスピン注入

    藤原直人, 谷山智康, 北本仁孝, 山崎陽太郎

    第25回日本応用磁気学会学術講演会   2001

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  • NiZn Ferrite Coating for Electrical Insulation of MnZn Ferrite Cores

    Y. Nakayama, H. Yajima, Y. Kitamoto, M. Abe

    Journal of the Korean Ceramic Society   38 ( 6 )   506 - 508   2001

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  • Magnetic and Mossbauer Study of Sr_2_FeMoO_6_ Partially Ordered Double Perovskite

    H. Sakuma, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    Journal of the Magnetics Society of Japan   25 ( 4-2 )   731 - 734   2001

  • Magnetotransport and Mossbauer study of Fe3O4/gFe2O3 granular thin films

    T.Taniyama, Y.Kitamoto, Y.Yamazaki

    Journal of Applied Physics   89 ( 11,Pt.2 )   7693 - 7695   2001

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  • Magnetic Anisotropy of Co-substituted Bi-DyAllG Nanoparticles

    T.Y. Kim, T. Taniyama, Y. Kitamoto, Y. Yamazaki, Y.D. Hong

    Journal of the Japan Society of Powder and Powder Metallurgy   48 ( 8 )   710 - 714   2001

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    The magnetic properties of the superparamagnetic Co-substituted Bi-DyAJIG (BiDy2CoxAlyFe5-x-yO12: 0≤x≤0.2, 0≤y≤1.1) nanoparticles were investigated. On the basis of the magnetic data, it is inferred that the magnetic moments of Dy ions cant from those of the iron ions. The canting angle was estimated to be 53°, which is larger than that previously observed in the sputtered films. The reason of the canting is possibly the surface and/or size effect of the nano-size garnet particles. The Co substitution was found to be effective to increase the coercive-force of the nanoparticles for magnetic recording storage media. The bifurcation temperature of zero-field-cooled (ZFC) and field-cooled (FC) magnetizations is also increased by the Co substitution. The ZFC and FC magnetization curves for the BiDy2CoxAly, Fe5-x-yO12 nanoparticles suggest that Co substitution enhances magnetic anisotropy of the nanoparticles, which is in accordance with increase in coercive-force Hc.

    DOI: 10.2497/jjspm.48.710

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  • Magneto-optical properties of Bi-YIG particle-composite Films prepared by different coprecipitaion procedures

    T. Taniyama C, S. Kuroda, Y. Kitamoto, Y. Yamazaki

    J. Magn. Soc. Japan   25 ( 3-2 )   311 - 312   2001

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    Magneto-optical Bi-YIG particles are prepared by different coprecipitation procedures. The crystallite size of the particle increases with the heat treatment temperature. In spite of a similar crystallite size, the saturation magnetization is considerably different by the coprecipitation procedure. The Faraday rotation of the composite film with the mixture of epoxy and the Bi-YIG particles linearly increases with the saturation magnetization for the film with crystallites smaller than 30 nm, while that for the film with larger crystallites deviates from the linearity and exhibits a decrease in the Faraday rotation. These results can be interpreted based on the scattering of the probing light due to the morphology of the composite film. The presence of a magneto-optically inactive surface region of the crystallite is also discussed.

    DOI: 10.3379/jmsjmag.25.311

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  • perpendicular Magnetic Orientation of co-substituted Bi-DyAlIG Nanoparticles for Magneto-Optical Strage Media

    T.Y.Kim, Y.Yamazaki, Y.Kitamoto, Y.D.Hong

    161   2001

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  • NiZn Ferrite Coating for Electrical Insulation of MnZn Ferrite Cores

    Y. Nakayama, H. Yajima, Y. Kitamoto, M. Abe

    Journal of the Korean Ceramic Society   38 ( 6 )   506 - 508   2001

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  • Magnetic and Mossbauer Study of Sr_2_FeMoO_6_ Partially Ordered Double Perovskite

    H. Sakuma, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    Journal of the Magnetics Society of Japan   25 ( 4-2 )   731 - 734   2001

  • Magnetic and Read/write Characteristics of CoNi Ferrite Perpendicular Recording Media with Soft Ferrite Underlayers

    Fuchun Zhang Nobuhiro Matsushita Masanori Abe, Yoshitaka Kitamoto

    International Conference on Materials for Advanced Technologies   2001

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  • Magnetic and recording characteristics of Co-Ni ferrite recording layers on soft ferrite underlayers

    Fuchun Zhang Nobuhiro Matsushita Masanori Abe, Yoshitaka Kitamoto

    The 8th Joint MMM-Intermag Conference   2001

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  • 多結晶La1-xSrMnO3薄膜における磁気伝導のアニール効果II

    濱屋宏平, 谷山智康, 北本仁孝, 山崎陽太郎

    第56回年次大会 日本物理学会講演概要集   354   2001

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  • Optimum Conditions for Preparing from Aqueous Solutions Co-Ni Ferrite Films for Perpendicular Magnetic Recording

    F. Zhang, Y. Kitamoto, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   1058 - 1060   2001

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  • ダブルペロブスカイト型酸化物Sr2FeMoO6のBサイトイオン配列と磁性

    佐久間洋志, 谷山智康, 北本仁孝, 山崎陽太郎

    第56回年次大会 日本物理学会講演概要集   389   2001

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  • Room Temperature Film Syntheses of Spinel Ferrites ((Fe, M)_3_O_4_, M=Fe, Co, Ni, and Zn) from Aqueous Solution

    K. Nishimura, N. Matsushita, Y. Kitamoto, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   615 - 617   2001

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  • Ferrite-plated Co_x_Fe_3-x_O_4_ Insulation Layers for Mn-Zn Ferrite Cores

    M. Sakai, Y. Nakayama, N. Matsushita, Y. Kitamoto, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   657 - 659   2001

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  • High-Density Magnetic Recording Application of Co Ferrite Thin Films Prepared by Ferrite-Plating Technique

    Y. Kitamoto, F. Zhang, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   1061 - 1063   2001

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  • High Frequency (10 MHz~3GHz) Permeability of (Ni, Zn, Fe)_3_O_4_ Films Prepared by Ferrite Plating at 90℃

    D. Kuruma, M. Yamaguchi, S. Yabukami, Y. Kitamoto, N. Matsushita, K.I. Arai, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   503 - 505   2001

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  • Temperature (25-80℃) Dependence of Conditions for Synthesizing Magnetite Films by Ferrite Plating

    K. Nishimura, Y. Kohara, N. Matsushita, Y. Kitamoto, M. Abe

    Ferrite: Proceedings of The Eighth International Conference on Ferrites (ICF 8)   654 - 656   2001

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  • Annealing effects of magnetotransport in polycrystalline LSMO thin films

    Hamaya K., Taniyama T., Kitamoto Y., Yamazaki Y.

    Meeting abstracts of the Physical Society of Japan   55 ( 2 )   400 - 400   2000.9

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  • Magnetotransport and Mossbauer study of Fe_3O_4-γfe_2O_3 thin films

    Taniyama T., Kitamoto Y., Yamazaki Y.

    Meeting abstracts of the Physical Society of Japan   55 ( 2 )   400 - 400   2000.9

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  • Improving magnetic and recording characteristics of CoNi ferrite films for perpendicular recording layer

    ZHANG F., MATSUSHITA S., KITAMOTO Y., ABE M.

    24   290 - 290   2000.9

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  • Solution conditions for CoNi ferrite perpendicular magnetic recording thin films

    ZHANG Fuchun, KITAMOTO Yoshitaka, ABE Masanori

    IEICE technical report. Magnetic recording   100 ( 188 )   1 - 4   2000.7

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    CoNi ferrite thin films were prepared for perpendicular magnetic recording media by spin-spray ferrite-plating method. In this paper, solution conditions for CoNi ferrite plating were optimized to increase coercivity H_<c⊥> and remanence ratio (M_r/M_s)_⊥ in perpendicular direction to the film plane. By adjusting the deposition rate, the concentration of NaCo_2 to optimize the ratio of Fe^<2+> to Fe^<3+> in the films and the concentration of CH_3COONH_4 to optimize pH in oxidizing solution, CoNi ferrite films with H_<c⊥> of 3200 Oe and (M_r/M_s)_⊥ of 0.6 were obtained without any heat-treatment. Disk media exhibited reproduced waveforms of di-pluse shape and better frequency responses.

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  • 磁性材料 フェライトめっきによるマグネタイト膜の生成条件

    西村一寛, 小原義久, 北本仁孝, 阿部正紀

    粉体粉末冶金協会講演概要集   2000   118   2000.5

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  • Effect of Ni addition into Co ferrite thin films for perpendicular recording media

    F Zhang, Y Kitamoto, M Abe, M Naoe

    JOURNAL OF APPLIED PHYSICS   87 ( 9 )   6881 - 6883   2000.5

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  • Increase in perpendicular coercivity of Co-Ni ferrite-plated films by Zn ferrite underlayers

    Y Kitamoto, F Zhang, M Abe, M Naoe

    JOURNAL OF APPLIED PHYSICS   87 ( 9 )   6878 - 6880   2000.5

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  • Spin-dependent intergranular transport in magnetite films deposited by ferrite plating

    Y Kitamoto, Y Nakayama, M Abe

    JOURNAL OF APPLIED PHYSICS   87 ( 9 )   7130 - 7132   2000.5

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  • Room temperature synthesis of magnetite films by ferrite plating

    NISHIMURA Kazuhiro, KITAMOTO Yositaka, ABE Masanori

    2000 ( 28 )   45 - 49   2000.2

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  • Development of Perpendicular Magnetic Recording Media Prepared by Co Ferrite-Plating Method

    ZHANG Fuchun, KITAMOTO Yoshitaka, ABE Masanori, KANTAKE Shuusuke

    2000 ( 28 )   51 - 54   2000.2

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  • Faraday rotation in annealed granular Co-SiO_2_ films

    E. Takeda, S. Seino, F. Shirasaki, Y. Kitamoto, M. Abe

    Trans. Mater. Res. Soc. Jpn   25 ( 1 )   11 - 14   2000

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  • Microstructure and magnetic properties of ferrite thin films prepared by sputtering and plating

    Yoshitaka Kitamoto, Shigeki Nakagawa, Masanori Abe, Masahiko Naoe

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   47 ( 2 )   165 - 170   2000

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    DOI: 10.2497/jjspm.47.165

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  • Solution conditions for CoNi ferrite perpendicular magnetic recording thin films

    Fuchun Zhang, Yoshitaka Kitamoto, Masanori Abe

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   47 ( 7 )   730 - 732   2000

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    DOI: 10.2497/jjspm.47.730

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  • Magnetoresistance in Magnetite Films Prepared by Ferrite Plating

    KITAMOTO Y., NAKAYAMA Y., ABE M.

    Journal of the Magnetics Society of Japan   24 ( 4-2 )   619 - 622   2000

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    Fe3-xO4 films prepared by ferrite plating exhibited negative magnetoresistance associated with spin-dependent intergranular transport. The Fe3-xO4 plated films were composed of Fe3O4, γ-Fe2O3, α-FeOOH, and γ-FeOOH. We investigated the relationship between the concentration of NaNO2 in the oxidizing solution and annealing, and the degree of oxidation, magnetic properties, and current-in-plane (CIP) electrical properties. Resistivity was about 0.3-500 μcm, which is higher than that of bulk magnetite (10-2 μcm). MR ratios taken in the maximum field of 2.5 kOe increased as much as 5.7% with increasing concentrations of NaNO2. Mössbauer spectroscopy and electrical evaluation showed that an increase in Fe3+ ion content, in other words, an increase in insulating region, raised the resistivity and the MR ratio with increasing concentrations of NaNO2. The temperature dependence of the resistivity suggested that the magnetoresistance is caused by spin-dependent tunneling through the insulating region that existed in the grain boundaries.

    DOI: 10.3379/jmsjmag.24.619

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  • Ni addition into Co ferrite-plated films

    Fuchun Zhang, Yoshitaka Kitamoto, Masanori Abe

    Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   47 ( 2 )   171 - 174   2000

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    DOI: 10.2497/jjspm.47.171

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  • Room-temperature Syntheis of Magnetite Films by Ferrite Plating

    NISHIMURA K., KOHARA Y., KITAMOTO Y., ABE M.

    Journal of the Magnetics Society of Japan   24 ( 4-2 )   515 - 517   2000

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    Fe3O4 (magnetite) films were successfully grown at room temperature by ferrite plating from an aqueous solution of FeCl2, utilizing Fe2+ → Fe3+ oxidation realized by adding an aqueous solution of NaNO2 + NH3 to the FeCl2 solution. Since we found that the Fe2+/Fe3O4 (solid) boundary line in the potential-pH diagram of iron shifts to the higher pH region, we increased the pH of the aqueous solution from 5.0-6.8 (at which previous plating was performed at 60°C-100°C) to 7.7-8.8. This facilitated the formation of magnetite films, which consist of single-phase magnetite, as revealed by X-ray diffraction. The magnitude of the films' saturation magnetization is equal to that of bulk samples. The film deposition rate was measured as a function of the pH and the concentration of NaNO2.

    DOI: 10.3379/jmsjmag.24.515

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  • Electrical and Magnetic Properties of Magnetite Films Prepared by Ferrite Plating

    Y. Nakayama, T. Ishikawa, Y. Kitamoto, M. Abe

    Trans. Materials Research Society of Japan   25 ( 4 )   1151 - 1154   2000

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  • Preparation of Hexaferrite Thin Films by Chelation Ferrite Plating with Post Deposition Annealing

    N. Matsushita, M. Ohnishi, S. Miyazaki, Y. Kitamoto, M. Abe

    Ferrites: Proceedings of 8th Inter. Conf. Ferrites(ICF8)   660 - 662   2000

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  • Conditions for Synthesizing Magnetic Films at Room Temperature by Ferrite Plating: Discussion Based on Equilibrium Kinetics

    Kazuhiro Nishimura, Yoshihisa Kohara, Yoshitaka Kitamoto, Masanori Abe

    Trans. Materials Research Society of Japan   25 ( 4 )   1187 - 1190   2000

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  • 反応生成物をバリアとしたLa_1-x_Sr_x_MnO_3_薄膜の低磁場磁気抵抗効果

    浜屋宏平, 谷山智康, 北本仁孝, 山崎陽太郎

    第24日本応用磁気学会学術講演概要集   191   2000

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  • Ferrite Plating of Styrene-Glycidyl Methiacrylate Laetx Particles for Bioseparation and DNA Diagnosis

    M. SAKAI, N. MATSUSHITA, Y, KITAMOTO, H. KAWAGUCHI H, HANDA M. ABE

    Ferrites: Proceedings of 8th Inter. Conf. Ferrites(ICF8)   111 - 113   2000

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  • ダブルぺロブスカイト型酸化物Sr_2_FeMoO_6_の磁気構造

    佐久間洋志, 谷山智康, 北本仁孝, 山崎陽太郎

    第24日本応用磁気学会学術講演概要集   55   2000

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  • Arイオンミリング法によるLSMO薄膜の微細加工、

    直江昌武, 浜屋宏平, 谷山智康, 北本仁孝, 山崎陽太郎

    第24日本応用磁気学会学術講演概要集   88   2000

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  • Bi-TIG Particles Prepared bu Different coprecipitation Procedure

    C.S. Kuroda, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    第24日本応用磁気学会学術講演概要集   237   2000

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  • Microfabrication of LSMO Wires by Dry Eching Process,

    M. Naoe, T. Taniyama, Y Kitamoto, Y. Yamazaki

    Digests of PMRC 2000   115   2000

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  • Spin-Dependent Intergranular Transport in Magnetite Films Deposited by Ferrite Plating

    Y. Kitamoto, Y. Nakayama, M. Abe

    J. Appl. Phys.   87 ( 9 )   7130 - 7132   2000

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  • Depoisition Rate of Magnetite Films Synthesized by Ferrite Plating at Room Temperature

    NISHIMURA Kazuhiro, KOHARA Yoshihisa, KITAMOTO Yoshitaka, ABE Masanori

    J. Jpn. Soc. Powder Powder Metallurgy   47 ( 7 )   733 - 736   2000

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    Magnetite (Fe3O4) films were successfully grown at 24°C from an aqueous solutions of FeC12 into which an oxidizing solution of (1) NaNO2 + NH3 (pH-adjuster) +CH3COONH4 (pH-buffer), (2) NaNO2+NH3+NH4C1(pH-buffer), or (3) NaNO2+NH3, was added. Films of single phase Fe3O4, as revealed by X-ray diffractometry, were obtained at pH=8-9. The pH value is increased from pH=5-7 at which single phase Fe3O4 films were synthesized previously at 60°C, as predicted from theory. The deposition rates of the Fe3O4 films take maximum values of 2.3 nm/min., 11.4 nm/min., and 6.3 nm/min. when oxidizing solution of (1), (2) and (3) were used, respectively. The films grown using the oxidizing solution. (3) were smooth in surface but those grown using (1) and (2) had rough surfaces.

    DOI: 10.2497/jjspm.47.733

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  • Effect of Zn Ferrite Underlayers on Magnetic Properties and Recording Characteristics for Co-Ni Ferrite Media

    F. Zhang, Y. Kitamoto, M. Abe

    Trans. Materials Research Society of Japan   25 ( 4 )   1175 - 1178   2000

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  • Ferrite Thin Film Devices Fabricated by Low Temperature Processing in Aqueous Solution

    Masanori Abe, Kazuhiro Nishimura, Yoshitaka Kitamoto

    The Minerals, Metals & Materials Society   219 - 224   2000

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  • Magnetoresistance in Magnetite Films Prepared from Aqueous Solution at Room Temperature

    K. Nishimura, Y. Kohara, Y. Kitamoto, M.Abe

    J. Appl. Physics   87 ( 9,Pt.3 )   7127 - 7129   2000

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  • Magnetic material. Deposition rate of magnetite film by the room temperature ferrite plating.

    NISHIMURA KAZUHIRO, KOHARA YOSHIHISA, KITAMOTO YOSHITAKA, ABE MASANORI

    粉体粉末冶金協会講演概要集   1999   227   1999.11

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  • Developing Perpendicular Magnetic Recording Media by Ferrite Plating from Aqueous Solution

    ABE M., KITAMOTO Y.

    IEICE technical report. Magnetic recording   99 ( 420 )   57 - 63   1999.11

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    For applying to perpendicular magnetic recording, ferrite films are prepared by ferrite plating from an aqueous solution at 85-90℃; Co-ferrite films for recording media and NiZn ferrite films for high permeability underlayers. The Co-ferrite films have a prominent perpendicular magnetic anisotropy, exhibiting excellent magnetic hysteresis loops with Hc=&sim;3200Oe. This paper describes improvement of magnetic properties of the ferrite films by optimizing plating conditions, and reports preliminary results of signal retrieval performed on the Co-ferrite films.

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  • フェライトめっき法によるマグネタイト膜の室温

    西村一寛, 小原義久, 北本仁孝, 阿部正紀

    日本応用磁気学会学術講演概要集   23   400   1999.10

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  • Magnetic properties and recording performance of CoNi ferrite perpendicular media

    KITAMOTO Y., ZHANG F., ABE M., NAOE M.

    23   36 - 36   1999.10

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  • Magnetoresistance in magnetite films prepared by ferrite plating

    KITAMOTO Y., NAKAYAMA Y., ABE M.

    23   504 - 504   1999.10

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  • Intergranular coupling and activation volume of Co-Ni ferrite thin films with high coercivity above 3 kOe

    Y Kitamoto, F Zhang, S Kantake, F Shirasaki, M Abe, M Naoe

    IEEE TRANSACTIONS ON MAGNETICS   35 ( 5 )   2694 - 2696   1999.9

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  • Nanostructured oxide films by ferrite plating with sonochemistry

    Y Kitamoto, M Abe

    NANOSTRUCTURED MATERIALS   12 ( 1-4 )   41 - 44   1999.7

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  • Co ferrite films with excellent perpendicular magnetic anisotropy and high coercivity deposited at low temperature

    Y Kitamoto, S Kantake, F Shirasaki, M Abe, M Naoe

    JOURNAL OF APPLIED PHYSICS   85 ( 8 )   4708 - 4710   1999.4

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  • Low-temperature fabrication of Co ferrite thin films with high coercivity for perpendicular recording disks by wet process

    Y Kitamoto, S Kantake, F Shirasaki, M Abe, M Naoe

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   193 ( 1-3 )   97 - 100   1999.3

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  • Co-Ferrite Perpendicular Magnetic Recording Media Prepared by Spin-Spray Ferrite-Plating

    F. Zhang, S. Kantake, Y. Kitamoto, M. Abe

    Trans. Mater. Res. Soc. Jpn.   24 ( 4 )   651 - 653   1999

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  • Magnetite film growth at 30℃on organic monomolecular layer, mimicking bacterial magnetosome synthesis

    M. Abe, T. Ishihara, Y. Kitamoto

    J. Appl. Phys.   85 ( 8, Pt.2B )   5705 - 5707   1999

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  • Spin-Spray Ferrite-Plated Co Ferrite Films with High Coercivity for Perpendicular Magnetic Recording Media

    Fuchun Zhang, Shusuke Kantake, Yoshitaka Kitamoto, Masanori Abe

    IEEE Trans. Magn.   35 ( 5,Pt.1 )   2751 - 2753   1999

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  • Nanostructured oxide films by ferrite plating with sonochemistry

    Yoshitaka Kitamoto, Masanori Abe

    Nanostructured Materials   12 ( 1 )   41 - 44   1999

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    DOI: 10.1016/S0965-9773(99)00062-8

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  • Electro-Ferrite Plating of Magnetite at 24-80℃

    Kazuhiro Nishimura, Yoshitaka Kitamoto, Masanori Abe

    IEEE Trans. Magn.   35 ( 5,Pt.1 )   3043 - 3045   1999

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  • Temperature Dependence of Films Deposition Rate in Electro-Ferrite Plating of Magnetite

    K. Nishimura, Y. Kitamoto, M. Abe

    Proc. 2nd Magneto-Electronics Int. Symp.   415   1999

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  • Electro-Ferrite Plating of Fe_3_O_4_ Films from Aqueous Solutions of FeCl_2_ Mixed with Various pH-Adjusting Solutions

    Kazuhiro Nishimura, Yoshitaka Kitamoto, Masanori Abe

    Trans. Mater. Res. Soc. Jpn.   24 ( 4 )   663 - 665   1999

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  • Deposition Rate of Magnetite Films Prepared by Electroless Ferrite Plating

    K. Nishimura, Y. Kitamoto, M. Abe

    Proc. 2nd Magneto-Electronics Int. Symp.   101   1999

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  • MR Effect of Magnetite Films Prepared by Ultrasound-Enhanced Ferrite Plating

    Y. Nakayama, S. Kuwabara, Y. Kitamoto, M. Abe

    Trans. Mater. Res. Soc. Jpn.   24 ( 4 )   643 - 645   1999

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  • Preparation of Ferrite Films for Electrical Insulation by Ultrasound-Enhanced Ferrite Plating

    Y. Nakayama, H. Yajima, Y. Kitamoto, M. Abe

    IEEE Trans. Magn.   35 ( 5,Pt.1 )   3040 - 3042   1999

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  • The Magnetic Recording Characters of Co Ferrite Perpendicular Magnetic Recording Media Prepared By Solution Process

    ZHANG Fuchun, KANTAKE Shuusuke, KITAMOTO Yoshitaka, ABE Masanori

    1998 ( 216 )   17 - 19   1998.12

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  • Effect of solution component in Fe_3O_4 Electroplating

    NISHIMURA Kazuhiro, KITAMOTO Yositaka, ABE Masanori

    1998 ( 216 )   11 - 16   1998.12

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  • Enhanced Phenomenon of Magneto-optical Effect in Photonic Crystal

    TAKEDA Eishi, ABE Masanori, SHIRASAKI Fumio, KITAMOTO Yoshitaka, INOUE Mitsuteru, ARAI Ken Ichi

    1998 ( 201 )   49 - 53   1998.12

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  • Magneto-optical and Optical Characterization of Granular Co-Au and Co-AlO_x Films

    TAKEDA E., TODOROKI N., KITAMOTO Y., ABE M., OHNUMA S., MASUMOTO K., GORODETSKY Gad, INOUE M., ARAI K. I.

    IEICE technical report. Magnetic recording   98 ( 281 )   17 - 22   1998.9

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    We have performed exprimental and theortical researches of optical and magneto-optical properties in granular magnetic structures in which magnetic ultra-fine particles were dispersed in non-magnetic matrices.Granular Ni-PVC films prepares by apin coating method exhibited Faraday effect(Faraday rotation)2〜3 times stronger than that calculated from using effective dielectric permeability as complex medium.In granular Co-SiO_2 and Fe-SiO_2 films perpared by RF sputter deposition, similar enhancement of Faraday effect were observed in the process of increasing magnetic particle in size by annealing. These enhancement of magneto-optical effect in granular C0-Au and Co-AlO_x films prepared by vacuum evaporation and sputtering, respectively, will be discussed relating to improvement of crystal structure and localization of light in disordered media.

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  • 超音波励起・フェライトめっき法--プラスチック超微粒子をフェライトで被覆する

    阿部 正紀, 北本 仁孝

    超音波techno   10 ( 6 )   29 - 32   1998.6

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  • 2)垂直磁気異方性Coフェライト膜の作製(<100℃)(画像情報記録研究会)

    北本 仁孝, 寒竹 秀介, 白崎 文雄, 高谷 慎一, 阿部 正紀

    映像情報メディア学会誌 : 映像情報メディア   52 ( 3 )   294 - 294   1998.3

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  • 垂直磁気ディスク用Co基合金/Ni-Znフェライト二層膜に関する研究 Reviewed

    北本仁孝

    1998.1

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  • Preparation of Co Ferrite Thin Films for Magnetic Recording Media by the Ferrite-Plating Method

    YOSHITAKA KITAMOTO

    Journal of The Magnetics Society of Japan   22 ( 4-2 )   477 - 479   1998

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    Perpendicular anisotropic CoxFe3-xO4 films 25-200 nm in thickness for perpendicular magnetic recording media were successfully obtained by the spin-spray ferrite-plating method at 90°C. The perpendicular coercivity Hc⊥of the films took a maximum at around 0.5, and the value of Hc⊥ was over 2000 Oe even for a film thickness of 25 nm. By optimizing the concentration of NaNO2 in the oxidizing solution, the in-plane coercivity Hc// was reduced to 300 Oe, while Hc⊥ was kept at over 2000 Oe. Mössbauer analyses show that the films have excellent perpendicular magnetic anisotropy. The angular dependence of the coercivity shows that a reversal of the magnetization takes place in the rotation mode as in Co-Cr sputter-deposited films.

    DOI: 10.3379/jmsjmag.22.477

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  • Ferrite-Plated Films and Their Applications

    ABE Masanori, KITAMOTO Yoshitaka

    Jitsumu Hyomen Gijutsu   49 ( 7 )   728 - 733   1998

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    Language:Japanese   Publisher:The Surface Finishing Society of Japan  

    DOI: 10.4139/sfj.49.728

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  • Preparation of Co Ferrite Thin Films for Magnetic Recording Media by the Ferrite-Plating Method

    KITAMOTO Y., KANTAKE S., TAKAYA S., SHIRASAKI F., ABE M., NAOE M.

    Journal of the Magnetics Society of Japan   22 ( 4-2 )   477 - 479   1998

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    Perpendicular anisotropic CoxFe3-xO4 films 25-200 nm in thickness for perpendicular magnetic recording media were successfully obtained by the spin-spray ferrite-plating method at 90°C. The perpendicular coercivity Hc⊥of the films took a maximum at around 0.5, and the value of Hc⊥ was over 2000 Oe even for a film thickness of 25 nm. By optimizing the concentration of NaNO2 in the oxidizing solution, the in-plane coercivity Hc// was reduced to 300 Oe, while Hc⊥ was kept at over 2000 Oe. Mössbauer analyses show that the films have excellent perpendicular magnetic anisotropy. The angular dependence of the coercivity shows that a reversal of the magnetization takes place in the rotation mode as in Co-Cr sputter-deposited films.

    DOI: 10.3379/jmsjmag.22.477

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  • Preparation of Co ferrite thin films for magnetic recording media by "Ferrite-plating" method

    KITAMOTO Y., KANTAKE S., TAKAYA S., SHIRASAKI F., ABE M., NAOE M.

    21   452 - 452   1997.10

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  • NiZn Ferrite Film Preparation by Ultrasound-Enhanced Ferrite Plating

    YAJIMA H., NAKAYAMA Y., KITAMOTO Y., ABE M.

    21   448 - 448   1997.10

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  • Enhancement of magneto-optical properties for Co/SiO_ and Fe/SiO_2 granular films

    SEINO S., SATO I., MATSUMIYA H., SHIRASAKI F., KITAMOTO Y., ABE M.

    21   403 - 403   1997.10

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  • Measurement and analysis of magneto-optical properties for granular magnetic thin films

    SEINO S., KITAMOTO Y., ABE M.

    IEICE technical report. Magnetic recording   97 ( 245 )   37 - 43   1997.9

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    We studied the optical and magneto-optical properties of granular films in which magnetic fine particles are dispersed in the binders. The Ni/PVC granular films, prepared by spin coating with Ni fine particles dispersed in PVC matrix, exhibited faraday effect 2〜3 times stronger than that calculated using effective dielectric permeability tensor for the films. This was not satisfactorily explained even by considering the effect of congelation of the Ni powders in the matrix, indicating that magneto-optical effect is enhanced in the granular structure. Faraday effect in sputter-deposited Co/SiO_2 and Fe/SiO_2 granular films increased as the Co and Fe particles increased in size by annealing, which, however, decreased as the particles size further increased by annealing.

    CiNii Books

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  • Ferromagnetic Film Preparation by Ultrasound-Enhanced Ferrite Plating

    YAJIMA Hiroshi, NAKAYAMA Yoshiyasu, KITAMOTO Yoshitaka, ABE Masanori

    IEICE technical report. Magnetic recording   97 ( 245 )   21 - 27   1997.9

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    Language:Japanese   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Ferrite plating enables crystalline spinel ferrite films to be grown form an aqueous solution at low temperature (< 100℃). This facilitates the fabrication of new ferrite film devices using non-heat-resistant materials as substrates. Combining the ferrite plating with sonochemistry, application of power ultrasound waves to stimulate chemical reactions, we successfully improved the crystallising, and therefore the quality of the films. Modifying the reaction cell and plating conditions further improved the film quality.

    CiNii Books

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  • Sputter-deposition of Co-Cr-Ta alloy layers on Ni-Zn ferrite plated underlayers

    Y Kitamoto, MH Kim, S Kantake, M Abe, M Naoe

    IEEE TRANSACTIONS ON MAGNETICS   33 ( 5 )   3085 - 3087   1997.9

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  • Ferrite Plated Films for Magnetic Recording Applications

    KITAMOTO Yoshitaka, KIM Myung-ho, KANTAKE Shusuke, ABE Masanori

    IEICE technical report. Magnetic recording   96 ( 486 )   37 - 43   1997.1

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    Language:Japanese   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Ferrite plating enables crystalline spinel ferrite films to be grown from an aqueous solution at low temperature (<100℃). We investigated internal stress and microstructure in the plated films to apply to backlayers for doublelayered perpendicular recording media. It is important to control surface morphology of the ferrite plated layers in order to deposit Co-Cr alloy layers with fine microstructure. To satisfy this requirement, it is necessary to accelerate migration of metal ions on growing films. Thus we tried power ultrasound enhancement for the ferrite plating.

    CiNii Books

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  • Preparation of Oxide Thin Films by Ferrite Plating and their Applications

    ABE Masanori, KITAMOTO Yoshitaka

    IEICE technical report. Magnetic recording   96 ( 246 )   1 - 8   1996.9

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    Language:Japanese   Publisher:The Institute of Electronics, Information and Communication Engineers  

    Ferrite plating enables crystalline spinel ferrite films to be grown from an aqueous solution at low temperature (<100℃). This technique facilitates the fabrication of new ferrite film devices on non-heat-resistant materials. This paper reports principles and features (in particular, low temperature process) of the ferrite plating, and applications such as magnetic recording media, microwave devices, and bio-medical applications. It also describes that power ultrasound irradiation during the ferrite plating improves the magnetic and structural properties of the plated films.

    CiNii Books

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  • A Novel Technique : Ultrasound enhanced Ferrite Plating, Applied to Ferrite-Capsulation of Polymer Microspheres

    ZHANG M., KITAMOTO Y., HAIJIMA S., MATSUMOTO K., ABE M.

    20   158 - 158   1996.9

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    CiNii Books

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  • Deposition of Co-Cr films with excellent C-axis orientation and uniform thickness for rigid disks using compact sputtering apparatus

    Y Kitamoto, M Abe, M Naoe

    IEEE TRANSACTIONS ON MAGNETICS   32 ( 5 )   4547 - 4549   1996.9

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  • Preparation of Co-Cr alloy/Ni-Zn ferrite doublelayered films for perpendicular magnetic tape

    Y Kitamoto, M Abe, M Naoe

    IEEE TRANSACTIONS ON MAGNETICS   32 ( 5 )   3834 - 3836   1996.9

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  • EFFECT OF SUBSTRATE-TEMPERATURE ON MAGNETIC AND MICROSTRUCTURAL PROPERTIES OF SPUTTERED CO-CR FILMS WITH PERPENDICULAR MAGNETIC-ANISOTROPY

    Y UCHIYAMA, H SATO, Y KITAMOTO

    IEEE TRANSACTIONS ON MAGNETICS   28 ( 5 )   2010 - 2017   1992.9

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  • PERPENDICULAR COERCIVITY OF CO-CR FILMS

    Y UCHIYAMA, H SATO, Y KITAMOTO, UM HWANG

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   30 ( 10 )   2485 - 2488   1991.10

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    Language:English  

    Web of Science

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  • Influence of Co-Zr-Nb Intermediate Layer on Properties of Double Layered Perperdicular Media

    Y. Uchiyama, H. Sato, Y. Kitamoto, K. Ishibashi, U. Hwang

    Journal of Magnetics Society Japan, Supplement   15 ( 52 )   995   1991

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  • Influence of Co-Zr-Nb Intermediate Layer on Properties of Double Layered Perperdicular Media

    Y. Uchiyama, H. Sato, Y. Kitamoto, K. Ishibashi, U. Hwang

    Journal of Magnetics Society Japan, Supplement   15 ( 52 )   995   1991

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  • CONTROL OF INTERNAL-STRESS OF CO-CR FILMS DEPOSITED BY FACING TARGETS SPUTTERING

    S NAKAGAWA, Y KITAMOTO, M NAOE

    IEEE TRANSACTIONS ON MAGNETICS   26 ( 1 )   106 - 108   1990.1

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  • Control of Internal Stress of Co-Cr Film Deposited by Facing Targets Sputtering

    Shigeki NAKAGAWA Yoshitaka, KITAMOTO, Masahiko NAOE

    IEEE Transactions on Magnetics   26 ( 1 )   106   1990

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  • Maltilayered Co-Cr Films with Non-Magnetic Intermediate Layers by FTS Systen.(共著)

    Y. Niimura, Y. Kitamoto, S. Nakagawa, M. Naoe

    IEEE Transactions on Magnetics   22 ( 5 )   2464   1987

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  • Maltilayered Co-Cr Films with Non-Magnetic Intermediate Layers by FTS Systen.(共著)

    Y. Niimura, Y. Kitamoto, S. Nakagawa, M. Naoe

    IEEE Transactions on Magnetics   22 ( 5 )   2464   1987

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Presentations

  • Fabrication of Langmuir-Blodgett film composed of Zinc Oxide nanoparticles

    2010 

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  • 磁気光学顕微鏡による(Ga,Mn)Asの磁化反転過程の局所観察

    第55回応用物理学関係連合講演会  2008 

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  • Langmuir-Blodgett法を用いた酸化亜鉛ナノ粒子薄膜の作製と評価

    2010 

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  • Influence of Chemical Conditions in Fabrication of Bi-YIG Precursor on Morphological and Magnto-Optical Response of Its Particulate Film

    2005 

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  • CoZrNb/Fe-C Discontinuous Multilayer Films for GHz Applications

    2005 

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  • High magnetocrystalline anisotoropy and thermal stability in isolated iron-platinum nanoparticle-monolayer with protective coating

    2005 

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  • CoZrNb/Fe-C Discontinuous Multilayer Films for GHz Applications

    2005 

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  • Synthesis of Fe-Pd nanoparticles by polyol reduction process and their magnetic properties

    2005 

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  • L10相Fe-Ni-Ptの製膜と磁気特性

    第29回日本応用磁気学会学術講演会  2005 

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  • Influence of Chemical Conditions in Fabrication of Bi-YIG Precursor on Morphological and Magnto-Optical Response of Its Particulate Film

    2005 

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  • Synthesis of Fe-Pd nanoparticles by polyol reduction process and their magnetic properties

    2005 

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  • High magnetocrystalline anisotoropy and thermal stability in isolated iron-platinum nanoparticle-monolayer with protective coating

    2005 

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  • Two magnetic phases in (Ga,Mn)As

    K. Hamaya, T. Taniyama, Y. Kitamoto, Y. Yamazaki

    The 49th Annual Conference on Magnetism & Magnetic Materials  2004 

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Awards

  • 粉体粉粉末冶金協会研究功績賞

    2021.6   粉体粉末冶金協会   磁性ナノ粒子及び集積体によるバイオメディカル応用のための材料・デバイス開発に関する研究

    北本 仁孝

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  • 粉体粉末冶金協会2010年度論文賞

    2011.5   粉体粉末冶金協会   FePt/SiO2複合型磁性ナノ粒子の作製

    渕上輝顕, 河村亮, 山崎陽太郎, 北本仁孝, 中川勝, 並木禎尚

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  • 日本応用磁気学会論文賞

    2000  

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  • コニカ画像科学奨励賞

    1999  

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    Country:Japan

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  • Young Researcher Award (IUMRS-ICA-97)

    1997  

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Research Projects

  • 磁性ナノ粒子-生体分子間相互作用による磁気緩和の変調と高感度バイオセンシング

    Grant number:21H01760  2021.4 - 2024.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    北本 仁孝

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    Grant amount:\17160000 ( Direct Cost: \13200000 、 Indirect Cost:\3960000 )

    生体分子である核酸、タンパク質、糖鎖、脂質と相互作用する仕組みを付加した酸化鉄ナノ粒子を作製し、各種生体分子と相互作用する様子を、形態的、光学的、磁気的に評価した。また、交流磁化計測装置開発においてはより高感度な計測回路の設計指針を示すことができた。加えて、計測した交流磁化の周波数特性の結果を解析する手法としてデータ科学に基づいた方法を開始し、その有効性を示すことがでた。
    DNA検出用磁性ナノ粒子プローブ開発においては、10塩基の単鎖DNAをプローブとして磁性ナノ粒子に固定化するプロセスを確立し、より分散性を向上させる溶液条件を明らかにした。創製した磁性ナノ粒子プローブを用いて22塩基のマイクロRNAを模したDNAと相互作用が起こることを交流磁化計測から明らかにした。その検出レベルは感染症などの検査のためのPCRにおいて検出する核酸のレベルと同等、あるいはより高感度になる可能性があることがわかった。
    交流磁化計測装置開発においては、生体分子と磁性ナノ粒子プローブとの間の複雑かつ不均一な生化学反応を交流磁化状態の分布計測を実現するための計測回路について検討した。詳細な分布計測のためには交流磁化の周波数特性において数1000点レベルの大量のデータが必要となるが、周波数をスキャンしながら高速で計測するための回路においてコンデンサなどの電子部品で回路のインピーダンスを調節することが有効であることを明らかにした。
    交流磁化の周波数特性において磁性ナノ粒子の磁化状態分布を解析するために、フィッティングや主成分分析を導入し、昨年度まで行っていたゲル中の磁性ナノ粒子の振舞を解析することにおいて、その有効性を示した。またより複雑な磁性ナノ粒子と高分子との相互作用について、その解析に適用できる可能性があることも示した。

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  • Biosensing by dynamic magnetization measurement of stimuli-responsive magnetic hydrogels

    Grant number:18H01824  2018.4 - 2021.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Kitamoto Yoshitaka

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    Grant amount:\17290000 ( Direct Cost: \13300000 、 Indirect Cost:\3990000 )

    Ferrogels composed of magnetic nanoparticles and stimuli-responsive hydrogels have been synthesized as a magnetic label for chemical/biochemical biosensors. Magnetic nanoparticles are dispersed in a stimuli-responsive polymer hydrogel with keeping a capability of physical motions such as rotation and vibration, exhibiting a magnetic relaxation (Brownian relaxation) based on their hydrodynamic behaviors against alternating magnetic fields. Modulations of the hydrodynamic behaviors of magnetic nanoparticles in the ferrogels have been detected by dynamic magnetization measurements of the ferrogels with a swelling behavior of a pH-responsive polymer hydrogel. The detection of ammonia gas has been successfully demonstrated using the pH-responsive ferrogel from the dynamic magnetization measurements.

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  • Ultrafast manipulation of magnetization with optical or lattice-wave excitations and its applications

    Grant number:22226002  2010.4 - 2016.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (S)

    Munekata Hiro, KITAMOTO Yoshitaka, NISHIBAYASHI Kazuhiro

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    Grant amount:\213460000 ( Direct Cost: \164200000 、 Indirect Cost:\49260000 )

    Manipulation of magnetization with femotosecond laser pulses has been studied in order to find ways to break the two-picosecond (ps) limit shown by magnetic pulses. The photo-excited precession of magnetization (PEPM) in ferromagnetic semiconductors is found to be attributed to the change in magnetic anisotropy due to photo-ionization of Mn ions, with which non-linear control of the precession amplitude has also been demonstrated by a pair of sub-ps-separated laser pulses. Furthermore, PEPM with MW/cm2 pulse power has been found possible in the Co-Pd multilayers, which indicates the discovery of candidate materials for spin-photonic devices. The spatial de-multiplexing of polarization modulated signals has been demonstrated using the optical fibers attached with magnetic thin films, through which fundamentals of spin-photonic devices are experimented. Helicity switching of circular polarized light at 100 kHz has been demonstrated at room temperature by dual-injection spin-LED.

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  • 磁性ナノ粒子プローブを用いた新型インフルエンザの超高感度迅速診断チップ

    Grant number:22300180  2010 - 2012

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    並木 禎尚, 北本 仁孝

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    Grant amount:\13520000 ( Direct Cost: \10400000 、 Indirect Cost:\3120000 )

    従来の簡易診断法の最小検出限界を低減できる超高感度・迅速な磁気バイオセンサチップを開発した。その実現のための要素技術は次の3点に集約され、これらの達成が本申請研究の目的である。
    1) 一次抗体被覆ナノ粒子・抗原複合体の磁気濃縮(微小空間での磁気分離による、希薄検体からの抗原抗体複合体の高効率捕捉)と、二次抗体によるシグナル増幅。
    2) マイクロ流路内のブラウン運動活性化と層流による抗原抗体反応の活性化。
    3) 高い交流磁界応答を示す磁性粒子プローブ、高感度センシング、磁性粒子-免疫複合体の物理的捕捉、トンネル磁気抵抗効果型磁気センサーと駆動回路技術から構成)。
    ・本成果により、新型インフルエンザの超早期診断率の大幅な向上が見込まれる。迅速・適切な対応が可能になるため、重症化・蔓延の防止に大きく貢献する。急増している新型インフルエンザは、従来型よりも致死率が高く、本申請は緊急性の高いテーマである。
    ・日本が世界をリードするナノテクノロジーを応用するため、日本の強みを活かせる。
    ・手のひらにのるサイズのハードディスクドライブのように小型化が可能で簡便なツールとなりうる。量産技術がある程度確立しているので、使い捨てと考えても余りコストがかからない。
    ・他疾患の診断にも応用できるため、大きな波及効果が期待できる。
    本年度は、抗原抗体反応を迅速・鋭敏に検出できる磁気バイオセンサチップを完成させ、特許出願、論文投稿、学会発表を行っている。

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  • Developing technology for imaging cancer tumors and sentinel lymph nodes utilizing sonic wave emission by magnetically stimulated particles

    Grant number:21240054  2009 - 2011

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    MATSUSHITA Nobuhiro, HANDA Hiroshi, KITAMOTO Yoshitaka, OGAWA Makoto, MINAMIYA Yoshihiro

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    Grant amount:\46670000 ( Direct Cost: \35900000 、 Indirect Cost:\10770000 )

    In order to apply to sentinel lymph node mapping by emission of acoustic waves by magnetically-stimulated particles, we developed new devices which will enable 3D magnetic particle imaging by using only one microphone. They are(1) Bunny ear Reflector Microphone(BERM) in which a microphone is mounted on a asymmetric position of a reflector and the impulse response of burst acoustic waves propagated directly and reflected by the reflector is analyzed. And(2)"Random Path Holophonic Sensor" in which the impulse response of burst ultrasonic waves propagated through the small apertures distributed randomly(after maximal-length sequences) on a microphone head is analyzed. Simulation experiments confirmed the operation principle of our new devices. We also developed "two-step ligand exchange reaction", by which we successfully synthesized ferrite beads with narrow size distribution ; when their average size was 20 nm they showed strong magneto-acoustic effect and they were accumulated at the first lymph nodes(pseudo sentinel lymph nodes) of a mouse at a high efficiency.

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  • Nano-magnetic sensing system for biomedical devices

    Grant number:20310077  2008 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KITAMOTO Yoshitaka, TSUGE Takeharu

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    Grant amount:\19240000 ( Direct Cost: \14800000 、 Indirect Cost:\4440000 )

    We studied developments of magnetic beads and magnetic sensors and their integration in a microfluidic device for detecting protein, DNA, virus, and etc in bio-medical applications. Magnetic beads, which is an assembly composed of Fe-Pt nanoparticles, were obtained using polymer dispersing agents, and they exhibited a high magnetic response. A fabrication process for magnetic-field sensors based on the tunneling-magnetoresistance effect and the integration into a microfluidic device were developed.

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  • Fabrication of innovative functional assemblies using programmed self-organizational processes

    Grant number:20200004  2008 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Innovative Areas (Research a proposed research project)

    ISHIKAWA Masamichi, MURATA Satoshi, KAJIKAWA Kotaro, KITAMOTO Yoshitaka

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    Grant amount:\31330000 ( Direct Cost: \24100000 、 Indirect Cost:\7230000 )

    Fabrication processes of formulating large-areal and defect-free assemblies for new functional materials were constructed based on programmed DNA self-organization and colloidal crystal theory. It was clearly presented that charged particles, e.g. colloidal particles and DNA assemblies, were self-organized into the crystalline structures of high perfection and large-area on charged substrates, such as glass and mica. The newly found mechanism was applied to fabricate thin-film photonic materials and meta-materials with noble optical properties.

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  • Elucidation and control of photo-magnetism in ferromagnetic semiconductors

    Grant number:19048020  2007 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Priority Areas

    MUNEKATA Hiro, KITAMOTO Yoshitaka

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    Grant amount:\43000000 ( Direct Cost: \43000000 )

    We report experimental accomplishments obtained through the study of light-induced precession of magnetization in ferromagnetic (Ga, Mn) As. In particular, non-thermal influence of optical excitation, coherent control of magnetization with two optical pulses, control of precession frequency, and optical generation of spin-current are described. Progress in the preparation and characterization of lateral-type spin LED is also described.

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  • Concentrated solar heat conversion to solar hydrogen using speciallycation-excess ferrite

    Grant number:19206106  2007 - 2008

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    TAMAURA Yutaka, ABE Masanori, KITAMOTO Masataka, KANEKO Hiroshi, HASEGAWA Noriko

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    Grant amount:\50050000 ( Direct Cost: \38500000 、 Indirect Cost:\11550000 )

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  • 磁性ナノファイバーの創製とマニピュレーション

    Grant number:16656094  2004 - 2005

    日本学術振興会  科学研究費助成事業  萌芽研究

    北本 仁孝

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    Grant amount:\2900000 ( Direct Cost: \2900000 )

    Coアセチルアセトナートを用いたポリオール還元法において,界面活性剤(オレイン酸)と高分子保護剤(trioctylphosphine oxide, TOPO)の両方を添加することによって,2-5nmの径でアスペクト比が10以上のファイバー状のナノ粒子が得られることをもとに検討を進めた.ファイバー状粒子の生成に対する要因のうち,オレイン酸とTOPOの共存,かつオレイン酸とTOPOの投入手順が大きく影響を及ぼすことがわかった.TOPOとCo錯体の比率を変えることによって球状Co粒子との生成割合が変化したが,ファイバー状粒子単独の磁性を評価するのに十分な精製が行なえるレベルには至らなかった.球状粒子では酸化が確認されなかったのに対し,ファイバー状粒子では酸化していることが確認されたが,酸化が粒子の生成中に起こったのか,生成後(精製中あるいは保存中)に起こったのかを断定することはできなかった.
    一方,高い磁気異方性を有する物質を用いてファイバー状のナノ粒子を形成することは磁気記録用に有効であると考えられる.そこで,L1_0規則合金であるFe-Pdナノ粒子の合成においてTOPOを保護剤として用いたが,生成するのは球状粒子のみであった.ファイバー状粒子の生成には析出した金属原子が鎖状のTOPOに配位することが必要であるが,元素による配位能の違いがファイバー状粒子が生成するかどうかに大きな影響を与えるものと推測できる結果であった.
    以上の結果から,本研究では試行することができなかったが,Coをベースとして耐酸化性にすぐれるPtなど貴金属との合金がファイバー状磁性微粒子の生成には適しているのではないかと推測される.

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  • Fabrication of magnetic nanoparticle-array recording media and their evaluation with probe heads

    Grant number:14350180  2002 - 2004

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KITAMOTO Yoshitaka, TANIYAMA Tomoyasu, MATSUSHITA Nobuhiro

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    Grant amount:\17000000 ( Direct Cost: \17000000 )

    The purpose of the present study is to establish fabrication techniques of Fe-Pt nanoparticle-array magnetic recording media and to evaluate their potential to achieve areal recording density over 1 tera-bit per square inch. The results are shown in the followings.
    1) We studied the relationship between chemical ordering and magnetic anisotropy for powder samples of Fe-Pt nanoparticles, and found that a volume ratio Q of ordered alloy phase evaluated with Mossbauer spectroscopy was a useful parameter to evaluate the chemical ordering. Whereas Q is a parameter for short-range ordering, S obtained from X-ray diffractometry is a parameter for long-range ordering. Magnetic anisotropy was evaluated with the maximum magnetic field of 90 kOe. Distribution of magnetic anisotropy-field H_k for partially ordered Fe-Pt nanoparticles was much broader than that for almost fully ordered Fe-Pt nanoparticles, and the low H_k components were included with a high volume ratio.
    2) Partially ordered Fe-Pt nanoparticles were successfully obtained with polyol reduction method of Fe and Pt salts by using microwave irradiation without any post-synthesis heat-treatment. The Fe-Pt nanoparticles synthesized at 250℃ with microwave irradiation exhibited volume ratio for ordered alloy phase of 60% and magnetic anisotropy field over 80 kOe.
    3) Mixing saturated fatty acid (C_nH_<2n> O_2) molecules to an Fe-Pt nanoparticle suspension assisted the formation of a nanoparticle monolayer on pure water surface without coagulation. Because the surface of the Fe-Pt nanoparticles is hydrophobic, interface energy with water surface is high. The fatty acid molecules probably reduced the interface energy as a buffer layer between the Fe-Pt nanoparticle-monolayer and water surface. Fatty acid molecules with n 【greater than or equal】 14 were effective for the formation, and the best one in view of the formation of regular nanoparticle-array was the molecule with n = 14.
    4) Carbon overcoats deposited with sputtering on Fe-Pt nanoparticle assembly-films successfully prevented the assembly-films from inter-particle sintering. Fe-Pt nanoparticles of 4-5 nm in diameter were kept isolated physically and were chemically ordered after an optimum heat-treatment. However, higher temperature and longer time for the heat treatment were required to achieve proper chemical ordering to fit a specification of high-density recording media for future recording system. Fe-Pt nanoparticle assembly-films with a carbon overcoat annealed under the optimum conditions exhibited that the particle size was 4-5 nm and magnetic anisotropy constant was 4.8x10^7 erg/cm^3.

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  • On-line System Designing for Multi Function DMFCs

    Grant number:13134202  2001 - 2005

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Priority Areas

    YAMAZAKI Yohtaro, KITAMOTO Fusao, KITAMOTO Yoshitaka, WAKI Keiko, TANIYAMA Tomoyasu, HAYASE Masanori

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    Grant amount:\125200000 ( Direct Cost: \125200000 )

    The Research Project D in the Priority Area conducted several studies related to the system development of direct type fuel cells. This group also developed various measurement systems and special analytical methods, to support the other Research Projects, i.e., Research Project A relating to the development of membrane materials, Research Project B relating to the studies of catalyst and electrode materials, and Research Project C relating to the study on the optimization of membrane and electrode assembly (MEA).
    The system development studies in the Project D include 3 tasks, i.e., (1) development of an ethanol fuel cell system as an alternative to the toxic DMFC fuel system, (2) development of PEFCs using alkaline polymer membrane materials, and (3) miniaturization of DMFCs using micro fabrication method.
    (1) A direct ethanol fuel cell is studied and the behavior of the acetaldehyde which is an intermediate product in the anode reaction was investigated. The knowledge obtained in this analysis contributes to the realization of direct ethanol fuel cells (DEFCs).
    (2) Alkaline fuel cells have the advantages that they lower the cathode overpotential, and they provide conditions suitable for catalysts without precious metals. We developed a fuel cell with alkaline membrane. The cell was tested for methanol, ethanol, 2-propanol fuels. The performance of the cell depended on the pH of the fuels. The improvement of the dispersion characteristic of carbon particles was the issue of the alkaline membrane fuel cells.
    (3) Novel micro DMFCs based on MEMS technology were designed and fabricated. The selective plasma etching method was employed to fabricate the gas channels in the cell. This technology reduces the number of the components in a DMFC and reduces the assembly cost as well as reduces their sizes.
    The TEM and SEM observation method for the cross section of MEA using a focused ion beam system, which was developed in this group, clarified the structure of the interface between the electrode and electrolyte membrane in the MEAs, and effectively supported the whole research project in the Priority Area.

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  • 金属磁性酸化物のナノ微細加工とスピン注入への応用

    Grant number:13875115  2001 - 2002

    日本学術振興会  科学研究費助成事業  萌芽研究

    山崎 陽太郎, 山内 尚雄, 谷山 智康, 北本 仁孝, 吉本 護

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    前年度,磁性酸化物であるマグネタイト薄膜の反応性イオンエッチングを確立したが,それと同様の反応を用いて,ペロブスカイト型マンガン酸化物を微細加工し,スピン注入デバイスの作製を行なった.まず,50ないし100nm厚のLa_<0.7>Sr_<0.3>MnO_3(LSMO)薄膜をSrTiO_3(001)基板上に,RFスパッタ法によりエピタキシャル成長させた.ポジ型レジストを塗布し,電子線リソグラフィにより1μm幅のリフトオフパターンを作製し,50nm厚のTi薄膜をマスクとして電子線蒸着により形成した.反応性イオンエッチングは,RFスパッタ装置を使用し,LSMO薄膜にはCO, NH_3混合ガスによって行なった.投入電力を75W,ガス圧力を0.02Torrと固定して,ガスの混合比を最適化し,CO : NH_3=1:4のときに3.8nm/minのエッチングレートを得た.TiマスクはCF_4ガスを用いた反応性イオンエッチングによって除去した.1μm幅のLSMO細線と直交するように0.5μm幅のCuFe近藤合金の細線をリフトオフにより形成した.スピン注入実験においては,金属系のスピン注入デバイスと同等の10^6A/cm^2程度の通電を行なったが,その際にCuFe部分で細線の断裂が起き,スピン注入によるCuFeの挙動の変化を捉えることはできなかった.その原因として,接合部分におけるジュール熱の発生があげられる.このことはLSMO表面が微細加工のダメージによりオーミック接合を得るのに適していなかったことを示唆していると考えられる.

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  • Development of Magnetooptical Plastic Fiber

    Grant number:12450265  2000 - 2002

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    YAMAZAKI Yohtaro, HIRANO Teruyoshi, TANIYAMA Tomoyasu, KITAMOTO Yoshitaka

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    Grant amount:\16700000 ( Direct Cost: \16700000 )

    This report describes a current sensor using Bi-YIG nanoparticle-dispersed optical prastic fiber with magnetooptical activity. Bi-YIG nanoparticles were prepared by coprecipitation followed by heat treatment. MMA was used for the matrix and PMMA was used for a dispersion agent in the matrix. Both optical absorption coefficient and magnetooptical properties such as saturation Faraday rotation and Veldet constant increased with increasing the volume fraction of the Bi-YIG particle in the fiber. Under the optimized conditions of the fiber length and the volume fraction the Veldet constant, which is the most important parameter for the current sensor, was 10 times as high as rare-earth doped glass. The most preferable wavelength of the optical source was 520 nm.
    Dispersability of the Bi-YIG particles improves the magnetooptical properties. Two additives for the coprecipitation were tried to improve the dispersibility, in other words, to improve grindability during the milling process. One was NaOH solution, and the other was ammonium sulfate. Adding NaOH solution decreased the crystallization temperature, leading to smaller particles after the milling process. TEM observation revealed that the Bi-YIG particles with the size of 20-40 nm were well dispersed in the case of the coprecipitation using NaOH and ammonium sulfate while coagulations exist in the case of the conventional process. The difference in the dispersibility led to the reduction in the absorption coefficient and the increase in the Faraday rotation. The maximum value of figure of merit reached 4.8, which is twice or higher than the conventional one.

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  • Micro-patterned high-density magnetic recording media by self-assembly in solution

    Grant number:11650343  1999 - 2000

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    KITAMOTO Yoshitaka, ABE Masanori, TANIYAMA Tomoyasu, YAMAZAKI Yohtaro

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    Grant amount:\3700000 ( Direct Cost: \3700000 )

    This report describes the preparation of a nanoparticles array for high-density magnetic recording media by a self-assembly process in a solution. Reverse micelle technique for preparing magnetic nanoparticles and self-assembly for arraying the particles were combined.
    It was found that pH values for preparing ferrite particles moved to higher range at low temperature below 60℃, which is the maximum temperature to employ the reverse micelle technique. An ammonia solution was superior to a NaOH solution regarding crystallinity and particle size for synthesizing magnetite or Co ferrite particles. While reaction temperature did not influence the particle size and crystallinity in the range from 25 to 55℃, saturation magnetization increased with increasing the temperature. However, all kinds of the particles obtained in this study exhibited super-paramagnetic properties at room temperature. Adding Co ions to the particles increased coercivity at 5 K, and the maximum value was higher than 10 kOe. However, the Co ferrite particles were still super-paramagnetic. Average particle size was about 10 nm. Transmission electron microscope (TEM) observation and electron diffraction pattern with nano-sized beam showed that a single particle was single crystal.
    TEM observation showed that some particles with the average size of 10 nm assembled and the others with the smaller size distributed without assembling. This result suggests that particles with a uniform size tend to assemble each other. In other words, the particles probably sort themselves with the similar size by self-assembling process.
    This tendency has an effect on manufacturing the array with uniform particles. Micropatternig of particulate films with the width of 2 mm and the pitch of 4 mm were tried with the help of self-assembling organic molecules in order to fabricate patterned magnetic recording media. However, the quality of the pattering was not as good as that of films of only the organic molecules.

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  • Preparation of oxide thim films by ultra-clean ferrite plating and their magnetic properties

    Grant number:09650346  1997 - 1998

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    KITAMOTO Yoshitaka, ABE Masanori

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    Grant amount:\3300000 ( Direct Cost: \3300000 )

    This report describes the ferrite plating using purified clean aqueous solutions to compress the formation of impurity particles, which are incorporated in plated films and degrade their microstructure and magnetic properties. To realize the ultra-clean solutions, 1) a reaction solution and an oxidizing one were prepared using ultrapure water and supplied through membrane filters of 0.1 mum in pore diameter, 2) an ammonia solution was supplied to keep a pH value during the reaction instead of CH_3COONH_4 that forms impurity particles by mixing with Fe^<2+> ions. Magnetite (Fe_3O_4) and Ni-Zn ferrite films were synthesized on glass substrates or polymer spheres.
    The polymer microspheres with ferrite coatings are used as carrier particles for enzyme immunoassay. The ferrite coatings are necessary for collecting the particles using magnetic field. Thickness of the ferrite coatings is required to be equal or less than 50 nm to obtain a good dispersion performance in water. In methods without using the clean solution technique, continuous films with such thickness were not obtained due to large grains of around 100 nm, which were caused by incorporated impurity particles formed in the solution. In the new method, small grains of 10-20 nm were observed in the initial stage. When the layer thickness was 50 nm, the polymer particles were fully encapsulated with ferrite coatings, which have smooth surface and were composed of uniform and small grains. Mossbauer spectra showed that the coatings are composed of magnetite. The saturation magnetization was almost the same as the bulk value. The particles coated with 50 nm-thick magnetite exhibited the excellent dispersion performance in water and efficiency of magnetic separation by the magnetic field of 40 Oe. These performances were superior to those of the product in the market for enzyme immunoassay.

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  • Preparation of magnetic films by new technique "ultrasound enhanced" ferrite plating

    Grant number:08455137  1996 - 1997

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ABE Masanori, SHIRASAKI Fumio, KITAMOTO Yoshitaka

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    Grant amount:\7800000 ( Direct Cost: \7800000 )

    Ferrite plating invented by the investigators enables formation of ferrite films from aqueous solution. Requiring no heat treatment, the ferrite plating facilitates fabrication of ferrite film devices using non-heat-resistant substances (e.g.plastics, nano-sized multilayrs, etc.) as substrates. In this study we combined the ferrite plating with sonochemical technology to improve the crystallinity and magnetic properties of the plated films. Applying power ultrasound waves (19.5kHz, 600W) to an FeCl_2 aqueous solution at 70゜C,we successfully encapsulated polyacrylate spheres of two sizes, 0.25 mum and 4.5mum in average diameter, with ferrite coatings of a magnetite-maghemite mixed solution. This broke the previous lower limit (0.3mum) of the size of the particles to be encapsulated ; without application of the ultrasound waves, the ferrite coating became discontinuous or insular. Applying high frequency ultrasound waves (1.6MHz, 20W) and the above low frequency ultrasound waves simultaneously, Fe_3O_4 films were successfully improved in surface smoothness and solubility limit of Ni ions in films of NiZn ferrite (Ni_<3-x-y> Ni_x Zn_y O_4) was increased from x=0.35 to 0.42. The marked improvements are ascribed to "hot spots" and "micro-stirring" caused by collapse of cavitation bubbles in the sonicated aqueous solution.

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  • 磁気記録媒体に関する研究

    科学研究費補助金 

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    Grant type:Competitive

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  • Study of magnetic nanoparticles and their applications

    Grant-in-Aid for Scientific Research 

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    Grant type:Competitive

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  • Study on Magnetic Recording Media

    Grant-in-Aid for Scientific Research 

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    Grant type:Competitive

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  • Study of microfabrication and spin transport for magnetic semiconductor

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    Grant type:Competitive

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  • 磁性半導体の微細加工とそのスピン伝導に関する研究

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    Grant type:Competitive

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  • 磁性ナノ粒子とその応用に関する研究

    科学研究費補助金 

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    Grant type:Competitive

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