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KAKIZAKI　Koichi
Mathematics, Electronics and Informatics DivisionProfessor
Department of Electrical Engineering,Electronics, and Applied Physics

Performance information

■ MISC
  • Annealing temperature dependences of ferroelectric and magnetic properties in polycrystalline Co-substituted BiFeO3 films　　　　　　　　　　　　　　　
    Hiroshi Naganuma; Jun Miura; Mitsumasa Nakajima; Hiromi Shima; Soichiro Okamura; Shintaro Yasui; Hiroshi Funakubo; Ken Nishida; Takashi Iijima; Masaki Azuma; Yasuo Ando; Kenji Kamishima; Koichi Kakizaki; Nobuyuki Hiratsuka
    JAPANESE JOURNAL OF APPLIED PHYSICS, Volume：47, Number：9, First page：7574, Last page：7578, Sep. 2008
    Multiferroic Co-substituted BiFeO3 films were fabricated by chemical solution deposition method followed by post deposition annealing at various temperatures. The substitution of Cobalt of B-sites for iron in BiFeO3 was promoted at relatively high temperatures. The B-site substitution by cobalt promoted increases in saturation magnetization and spontaneous magnetization By substitution. leakage Current density Was suppressed ill a high-electric-field region and ferroelectric hysteresis (P-E) loops became measurable even at room temperature. The optimal annealing temperature for the coexistence of a high remanent polarization and a high remanent magnetization was 923 K having a high B-site substitution ratio of cobalt.
    JAPAN SOC APPLIED PHYSICS, English
    DOI：https://doi.org/10.1143/JJAP.47.7574
    DOI ID：10.1143/JJAP.47.7574, ISSN：0021-4922, eISSN：1347-4065, CiNii Articles ID：150000051394, Web of Science ID：WOS:000259657800024
  • Simple process synthesis of BaTiO3-(Ni,Zn,Cu)Fe2O4 ceramic composite　　　　　　　　　　　　　　　
    Kenji Kamishima; Yoshitaka Nagashima; Koichi Kakizaki; Nobuyuki Hiratsuka; Kowashi Watanabe; Takaya Mise; Hiroshi Naganuma; Soichiro Okamura
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Volume：77, Number：6, First page：4, Jun. 2008
    Ceramic composites (2Ni(0.41)Zn(0.41)Cu(0.18)Fe(2)O(4)-BaTiO3) were successfully prepared by a direct solid-state reaction of raw materials (BaCO3, CuO, alpha-Fe2O3, NiO, TiO2, and ZnO). X-ray diffraction (XRD) and electron probe micro analysis (EPMA) measurements were performed for these samples and it is confirmed that the composites consist of spinel ferrite and BaTiO3 phases. The composites are so homogeneous that the ferrite and BaTiO3 grains do not react with each other and have radii in the range of 1-5 mu m. Hexagonal BaTiO3 (h-BaTiO3) can be made in this composite form with a sintering temperature of 1200 degrees C, although h-BaTiO3 can be usually synthesized above 1460 degrees C. The freezing-point depression of BaTiO3 takes place due to the mixing with the spinel ferrite, which may result in the formation of h-BaTiO3 at a low temperature of 1200 degrees C.
    PHYSICAL SOC JAPAN, English
    DOI：https://doi.org/10.1143/JPSJ.77.064801
    DOI ID：10.1143/JPSJ.77.064801, ISSN：0031-9015, Web of Science ID：WOS:000256893800041
  • Ferroelectric and magnetic properties of multiferroic BiFeO3-Based composite films　　　　　　　　　　　　　　　
    Hiroshi Naganuma; Tomosato Okubo; Kenji Kamishima; Koichi Kakizaki; Nobuyuki Hiratsuka; Soichiro Okamura
    IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, Volume：55, Number：5, First page：1051, Last page：1055, May 2008
    BiFeO3-based composite films were fabricated onto the Pt/Ti/SiO2/Si(100) substrates by a chemical solution deposition (CSD) method using the precursor solutions with various excess iron composition followed by annealing at 923 K for 30 minutes under oxygen gas flow. Coexistence of spontaneous magnetization and remanent polarization could be obtained in the BiFeO3-based composite films with high excess iron composition. The remanent magnetization of almost 20 emu/cm(3) and the magnetic coercive field of 1.5 kOe were obtained at the iron composition ratio of Fe/Bi = 1.25. In this specimen, the remanent polarization at 90 K was approximately 10 mu C/cm(2) at the electric field of 1500 kV/cm. Structural analysis suggested that the remanent polarization has a possibility to increase by suppressing the formation of the secondary phases of Bi2Fe4O9 and alpha-Fe2O3, these are the nonferroelectric material as well as antiferromagnetic phase.
    IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, English
    DOI：https://doi.org/10.1109/TUFFC.2008.755
    DOI ID：10.1109/TUFFC.2008.755, ISSN：0885-3010, CiNii Articles ID：120002070232, PubMed ID：18519211, Web of Science ID：WOS:000255537600021
  • 超低熱膨張性と排ガス浄化能を有する複合機能性ゼオライト多孔体の創製<研究成果報告>　　　　　　　　　　　　　　　
    柳瀬 郁夫; 柿崎 浩一; 小林 秀彦
    Volume：1, Number：38, First page：128, Last page：131, 2005
  • 超低熱膨張性と排ガス浄化能を有する複合機能性ゼオライト多孔体の創製<研究成果報告>　　　　　　　　　　　　　　　
    柳瀬 郁夫; 柿崎 浩一; 小林 秀彦
    埼玉大学紀要, 工学部, 第1部論文集, Volume：1, Number：38, First page：128, Last page：131, 2005
  • The effect of AIN underlayer on c-axis orientation of barium ferrite thin films for perpendicular magnetic recording media　　　　　　　　　　　　　　　
    K.Kakizaki; H.Watanabe; N.Hiratsuka
    Volume：235, Number：1/3, First page：169, Last page：173, 2001
    DOI：https://doi.org/10.1016/S0304-8853(01)00331-6
    DOI ID：10.1016/S0304-8853(01)00331-6, ISSN：0304-8853, CiNii Articles ID：80012712958
  • The effect of AIN underlayer on c-axis orientation of barium ferrite thin films for perpendicular magnetic recording media　　　　　　　　　　　　　　　
    K.Kakizaki; H.Watanabe; N.Hiratsuka
    J.Magn.Magn., Mat., Volume：235, Number：1/3, First page：169, Last page：173, 2001
    DOI：https://doi.org/10.1016/S0304-8853(01)00331-6
    DOI ID：10.1016/S0304-8853(01)00331-6, ISSN：0304-8853, CiNii Articles ID：80012712958
  • Magnetic Properties and Crystal orientation of La-Co Substituted Barium Ferrite Thin Films　　　　　　　　　　　　　　　
    K.Kakizaki; H.Taguchi; H.Nishio; N.Hiratsuka
    First page：636, Last page：638, 2000
  • Magnetic Properties of Pb Substituted Ba-ferrite Thin Films　　　　　　　　　　　　　　　
    KAKIZAKI K.; HIRATSUKA N.
    Journal of the Magnetics Society of Japan, Volume：24, Number：4-2, First page：519, Last page：522, 2000
    The effects of substituting Ba ions for Pb ions on low temperature preparation of barium ferrite thin films and on their magnetic properties were investigated. Ba1-XPbXFe12O19 thin films were deposited on a fused quartz substrate by an rf magnetron sputtering method. In order to control the composition of the deposited Ba1-XPbXFe12O19 films, several sintered BaFe2O4 chips and PbO chips were placed on the barium ferrite target. The film thickness was varied between 20 and 250 nm. As-deposited films were post-annealed at temperatures between 500 and 700°C for 5 hours in air.
    Ba1-XPbXFe12O19 films with Pb content of 0.24 or above were well crystallized by post-annealing at 550°C for 5 hours in air. Ba0.65Pb0.35Fe12O19 film, especially, showed excellent magnetic properties, and its grains were small and uniform. As the film thickness of Ba0.65Pb0.35Fe12O19 film was decreased, its coercivity increased; its value reached 5.0 kOe at t = 50 nm. Moreover, the Ba0.65Pb0.35Fe12O19 film had little interaction between grains and high thermal stability of magnetization.
    The Magnetics Society of Japan, Japanese
    DOI：https://doi.org/10.3379/jmsjmag.24.519
    DOI ID：10.3379/jmsjmag.24.519, ISSN：0285-0192, CiNii Articles ID：110002810723, CiNii Books ID：AN0031390X
  • Magnetic Properties and Crystal orientation of La-Co Substituted Barium Ferrite Thin Films　　　　　　　　　　　　　　　
    K.Kakizaki; H.Taguchi; H.Nishio; N.Hiratsuka
    Proc.8th.Int.Conf on Ferrites, First page：636, Last page：638, 2000
  • Pb置換Baフェライト薄膜の磁気特性　　　　　　　　　　　　　　　
    柿崎浩一; 平塚信之
    日本応用磁気学会誌, Volume：24, Number：4-2, First page：519, Last page：522, 2000
    The effects of substituting Ba ions for Pb ions on low temperature preparation of barium ferrite thin films and on their magnetic properties were investigated. Ba1-XPbXFe12O19 thin films were deposited on a fused quartz substrate by an rf magnetron sputtering method. In order to control the composition of the deposited Ba1-XPbXFe12O19 films, several sintered BaFe2O4 chips and PbO chips were placed on the barium ferrite target. The film thickness was varied between 20 and 250 nm. As-deposited films were post-annealed at temperatures between 500 and 700°C for 5 hours in air.
    Ba1-XPbXFe12O19 films with Pb content of 0.24 or above were well crystallized by post-annealing at 550°C for 5 hours in air. Ba0.65Pb0.35Fe12O19 film, especially, showed excellent magnetic properties, and its grains were small and uniform. As the film thickness of Ba0.65Pb0.35Fe12O19 film was decreased, its coercivity increased; its value reached 5.0 kOe at t = 50 nm. Moreover, the Ba0.65Pb0.35Fe12O19 film had little interaction between grains and high thermal stability of magnetization.
    The Magnetics Society of Japan, Japanese
    DOI：https://doi.org/10.3379/jmsjmag.24.519
    DOI ID：10.3379/jmsjmag.24.519, ISSN：0285-0192, CiNii Articles ID：110002810723, CiNii Books ID：AN0031390X
  • Magnetic Properties and Crystal Structure of Acicular Barium Ferrite Particles.　　　　　　　　　　　　　　　
    K.Kakizaki; N.Hiratsuka
    Volume：22, Number：S1, First page：129, Last page：131, 1998
  • Magnetic Properties and Crystal Structure of Acicular Barium Ferrite Particles.　　　　　　　　　　　　　　　
    K.Kakizaki; N.Hiratsuka
    J.Mag.Soc.Jpn., Volume：22, Number：S1, First page：129, Last page：131, 1998
  • Fine Structure of Acicular BaCoxTixFe12-2xO19 Particles and Their Magnetic Properties.　　　　　　　　　　　　　　　
    K.Kakizaki; N.Hiratsuka
    Volume：176, Number：1, First page：36, Last page：40, 1997
    DOI：https://doi.org/10.1016/S0304-8853(97)00634-3
    DOI ID：10.1016/S0304-8853(97)00634-3, ISSN：0304-8853, CiNii Articles ID：80010050137
  • Fine Structure of Acicular BaCoxTixFe12-2xO19 Particles and Their Magnetic Properties.　　　　　　　　　　　　　　　
    K.Kakizaki; N.Hiratsuka
    J.Magn.Magn.Mat., Volume：176, Number：1, First page：36, Last page：40, 1997
    DOI：https://doi.org/10.1016/S0304-8853(97)00634-3
    DOI ID：10.1016/S0304-8853(97)00634-3, ISSN：0304-8853, CiNii Articles ID：80010050137
  • ZnO-SnO_2系複合酸化物のイソブタンガス感度特性　　　　　　　　　　　　　　　
    平塚 信之; 細井 明子; 小林 裕; 柿崎 浩一
    Volume：104, Number：1216, First page：1158, Last page：1159, 1996
    DOI：https://doi.org/10.2109/jcersj.104.1158
    DOI ID：10.2109/jcersj.104.1158
  • ZnO-SnO_2系複合酸化物のイソブタンガス感度特性　　　　　　　　　　　　　　　
    平塚 信之; 細井 明子; 小林 裕; 柿崎 浩一
    日本セラミックス協会学術論文誌, Volume：104, Number：1216, First page：1158, Last page：1159, 1996
    DOI：https://doi.org/10.2109/jcersj.104.1158
    DOI ID：10.2109/jcersj.104.1158
■ Research projects
  • 磁気抵抗材料に関する研究　　　　　　　　　　　　　　　
    2003
    Competitive research funding
  • Study on magneto-resistance effect for magnetic thin films　　　　　　　　　　　　　　　
    2003
    Competitive research funding
  • 軟磁性グラニュラー薄膜に関する研究　　　　　　　　　　　　　　　
    2002
    Competitive research funding
  • Study on soft magnetic thin films with granular structure　　　　　　　　　　　　　　　
    2002
    Competitive research funding
  • 高密度磁気記録媒体に関する研究　　　　　　　　　　　　　　　
    1995
    Competitive research funding
  • Study on high density magnetic recording media　　　　　　　　　　　　　　　
    1995
    Competitive research funding
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