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THERMALLY STABLE ULTRA HIGH DENSITY THIN FILM MAGNETIC MEDIA

Research Project

Project/Area Number 10305027
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field 電子デバイス・機器工学
Research InstitutionTOHOKU UNIVERSITY

Principal Investigator

TAKAHASHI Migaku  GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIV. PROFESSOR, 大学院・工学研究科, 教授 (70108471)

Co-Investigator(Kenkyū-buntansha) SHOJI Hiroki  GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIV. ASSOCIATE PROFESSOR, 大学院・工学研究科, 助教授 (70241528)
Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 1999: ¥8,700,000 (Direct Cost: ¥8,700,000)
KeywordsMEDIA / THERMAL DECAY / THIN FILM / MAGNETIC RECORDING / DPUTTER / 薄膜磁気記録媒体 / 磁気余効 / 磁性結晶粒径 / 結晶磁気異方性エネルギー / ウルトラクリーンスパッタリングプロセス
Research Abstract

All the thin film media used in this study were prepared with an in-line thin film deposition machine, which has 6 separated chambers for sputtering. The ultimate vacuum pressure for each chamber was better than 3×10ィイD1-9ィエD1 Torr. To remove impurities from the substrate surface, prior to film deposition, dry-etching was performed by rf sputtering. The compositions of magnetic layer were CoCrPt, CoCrTaPt and CoCrPtB. The Cr, Pt, Ta B content was widely varied. The results get from the evaluation of magnetic properties, microstructure and read-write properties are written below.
1. The intergranular magnetic coupling and the grain size in CoCrPt media with B addition are both reduced. On the other hand, the substitution of Cr with Ta in CoCrPt media increases the grain size. The read-write evaluation shows that the addition of B into CoCrPt reduces the media noise significantly. However, the media noise of CoCrTaPt media is lower compared with CoCrPtB, though the CoCrTaPt media has larger grain size compared with CoCrPtB media. This is due the relatively lower intergranular exchange coupling in CoCrTaPt media, compared with CoCrPtB media. From this result, we can conclude that the addition of both Ta and B into CoCrPt media is effective to reduce the media noise.
2. To realize a media which is thermally stable, the thermal stability factor vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT must be larger than 85.
It is concluded that to realize low noise media which is thermally stable, the coercivity HィイD2cィエD2, the anisotropy field HィイD2kィエD2ィイD1grainィエD1 and the magnetocrystalline anisotropy energy KィイD2uィエD2ィイD1grainィエD1 should be 5 kOe, 14 kOe and 2.1×10ィイD16ィエD1 erg/cmィイD13ィエD1, respectively. With the assumption that the saturation magnetization is MィイD2sィエD2=300 emu/cmィイD13ィエD1, the squareness S=0.7, remanence magnetization MィイD1rィエD1=210 emu/cmィイD13ィエD1, film thickness tィイD2magィエD2=15 nm, vィイD2actィエD2KィイD2uィエD2ィイD1grainィエD1/kT=85, magnetic cluster GDィイD2actィエD2=12 nm.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] M.Takahashi: "Saturation Magnetization and Uniaxial Magnetocrystalline Anisotropy for Co Based Binary and Co-Ge-Cr Ternary Alloys"Applied Physics Letters. (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.Takahashi: "Challenge to a Physical Limit in Longitudinal High Density Recording Media"Journal of The Electrochemical Society. (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S.Yoshimura: "Grain Size Reduction by Utilizing Very Thin CrW Seedlayer and Dry-Etching Process in CoCrTaNiPt Longitudinal Media"Journal of Applied Physics. (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S.Yoshimura: "Magnetic and Structural Properties of CoCrTaNiPt Longitudinal Thin Film Media"Journal of Applied Physics. (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. Takahashi: "Saturation Magnetization and Uniaxial Magnetocrystalline Anisotropy for Co Based Binary and Co-Ge-Cr Ternary Alloys"Appl. Phys. Lett.. in press. (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. Takahashi: "Challenge to a Physical Limit in Longitudinal High Density Recording Media"J. Electrochem. Soc.. in press. (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshimura: "Grain Size Reduction by Utilizing Very Thin CrW Seedlayer and Dry-Etching Process in CoCrTaNiPt Longitudinal Media"J. Appl. Phys.. in press. (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] S. Yoshimura: "Magnetic and Structural Properties of CoCrTaNiPt Longitudinal Thin Film Media"J. Appl. Phys.. in press. (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.Takahashi: "Saturation Magnetization and Uniaxial Magnetocrystalline Anisotropy for Co Based Binary and Co-Ge-Cr Ternary Alloys"Applied Physics Letters. (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.Takahashi: "Challenge to a Physical Limit in Longitudinal High Density Recording Media"Journal of The Electrochemical Society. (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] S.Yoshimura: "Grain Size Reduction by Utilizing Very Thin CrW Seedlayer and Dry-Etching Process in CoCrTaNiPt Longitudinal Media"Journao of Applied Physics. (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] S.Yoshimura: "Magnetic and Structural Properties of CoCrTaNiPt Longitudinal Thin Film Media"Journal of Applied Physics. (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.Takahashi: "Effect of Pt on the Intergranalar Exchange Coupling in CoCrTaPt Thin Film Media Prepared under Ultra Clean Sputtering Process" Journal of the Magnetics Society of Japan. Vol.23,No.1-2. 335-337 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] M.Takahashi: "Effect of Film Thickness on Magnetic Proper fies and Microstructure for CaCrTa Media Fabricated under the ultra Clear Sputtering Process" Journal of the Magnetis Society of Japan. Vol.23,No.1-2. 739-741 (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] M.Takahashi: "Physics of High Density Recording Thin Film Media Established by Ultra Clean Sputtering Process" Journal of the Magnetis Society of Japan. (発表予定). (1999)

    • Related Report
      1998 Annual Research Report

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Published: 1999-04-01   Modified: 2016-04-21  

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