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Fabrication of Curie point written solid state magnetic memories

Research Project

Project/Area Number 13555092
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section展開研究
Research Field Electronic materials/Electric materials
Research InstitutionNagoya University

Principal Investigator

TSUNASHIMA Shigeru  Nagoya University, Dept.of Electronics, Professor, 工学研究科, 教授 (80023323)

Co-Investigator(Kenkyū-buntansha) KATO Takeshi  Nagoya University, Dept.of Electronics, Assistant Professor, 工学研究科, 助手 (50303665)
IWATA Satoshi  Nagoya University, CCRAST, Professor, 先端技術共同研究センター, 教授 (60151742)
Project Period (FY) 2001 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥13,600,000 (Direct Cost: ¥13,600,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2001: ¥8,600,000 (Direct Cost: ¥8,600,000)
Keywordssolid state magnetic momery / MRAM / spin tunneling junction / non-volatile memory / Blocking temperature / exchanae anisotropy / spin polarized transport
Research Abstract

Micropatterned amorphous films for thermomagnetic recording, TMR films using amorphous alloy layers, exchange biased films, and thermomagnetic recording process were investigated.
(1) TbFe amorphous alloy films were prepared by rf magnetron sputtering, and microfabricated by focused ion beam (FIB) and conventional photolithography methods. Switching of the magnetization of TbFe elements was confirmed after current pulses which give rise to Joule heat in the elements. The current density necessary for the switching was found to decrease with decreasing the element size, and the 0.5μm squared element was found to be switched by applying the current density as small as 1.6 x 10^6 A/cm^2. In addition, tunnel junctions including TbFe amorphous alloy layer was found to exhibit sufficiently large magneto resistance ratio.
(2) NiFe/Mnlr exchange biased films were microfabricated by FIB and their magnetic domain structures were observed by magnetic force microscopy (MFM). The easy direction of the NiFe/Mnlr elements lay in the film plane, and for such in-plane elements having 1 : 1 aspect ratio, it is difficult to obtain sigle domain state. Thus, the perpendicular magnetized elements such as TbFe were found to be effective to accomplish single domain state if the elements have 1 : 1 aspect ratio.
(3) Simulation of thermomagnetic recording process was carried out, and the simulation was used to obtain material parameters which are necessary for recording of domains smaller than 100 nm. For the recording of domains smaller than 50 nm on an RE-rich TbFeCo medium, the increase of coercivity, which might be realized by controlling the microstructure of the TbFeCo film, was found to be needed.

Report

(4 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • 2001 Annual Research Report
  • Research Products

    (28 results)

All Other

All Publications (28 results)

  • [Publications] S.Tsunashima: "Observation of thermomagnetically recorded domains with a high resolution magnetic X-ray microscope"Proc.SPIE. 5060. 81-88 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Ikeda: "Tunnel magnetoresistance effect and the magnetization process of GdFe/AI oxide/Co/TbFe junctions"Trans.Magn.Soc.Jpn.. 3. 109-113 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kume: "Exchange anisotropy of (001) oriented Mn_<1-X>Pt_X/NiFe epitaxial films"J.Appl.Phys.. 93. 6599-6601 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kato: "Temperature dependence of giant magneto-resistance in PtMn and Fe_2O_3 based specular spin valves"J.Magn.Magn.Mat.. 240. 168-170 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kato: "Magnetic domain structure of NiFe and Mnlr/NiFe elements patterned by focused ion beam"Jpn.J.Appl.Phys.. 41. L1078-L1080 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] S.Tsunashima et al.: "Observation of thermomagnetically recorded domains with a high resolution magnetic X-ray microscopy"Proc.SPIE. vol.5060. 81-88 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Ikeda et al.: "Tunnel magnetoresistance effect and the magnetization process of GdFe/Al oxide/Co/TbFe junctions"Trans.Magn.Soc.Jpn.. vol.3. 109-113 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kume et al.: "Exchange anisotropy of (001) oriented M_<1-x>Pt_x/NiFe epitaxial films"J.Appl.Phys.. vol.93. 6599-6601 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kato et al.: "Temperature dependence of giant magneto-resistance in PtMn and Fe_2O_3 based specular spin valves"J.Magn.Magn.Mat.. vol.240. 168-170 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kato et al.: "Magnetic domain structure of NiFe and Mnlr/NiFe elements patterned by focused ion beam"Jpn.J.Appl.Phys.. vol.41. L1078-L1080 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Kume: "Exchange anisotropy of (001) oriented Mn_<1-x>Pt_x/NiFe epitaxial films"J.Appl.Phys.. 93・10. 6599-6601 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Koyama: "Simulation of high density thermomagnetic recording process with magnetic field modulation method"Proc.of SPIE. 5060. 95-98 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Kato: "Magnetic anisotropy of MBE grown MnPt_3 and CrPt_3 ordered alloy films"J.Magn.Magn.Mat.. (発表予定). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Kume: "Exchange anisotoropy of MBE grown Mn1-xPtx/NiFe bilayers with (001) orieentation"J.Magn.Magn.Mat.. (発表予定). (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Kato: "Magnetic Circular Dichroism of Polycrystalline (Mn_<1-x>Cr_x)Pt_3 and Epitaxial CrPt_3 Alloy Films"Trans. Magn. Soc. Jpn.. 2-2. 98-103 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Kume: "Exchange anisotropy in epitaxial Mn_<1-x>Pt_<x/>NiFe bilayers"IEEE Trans. Magn.. 38-5. 2785-2787 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Koyama: "Simulation of thermomagnetic recording process using magnetic field modulation method"Trans. Magn. Soc, Jpn.. 2-4. 271-272 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Kato: "Magnetic domain structure of NiFe and MnIr/NiFe elements patterned by focused ion beam"Jpn. J. Appl. Phys.. 41-10A. L1078-L1080 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Kato: "Magnetic circular dichroism spectra of MnPt_3/Co multilayers"J. Magn. Magn. Mat.. 240. 517-519 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Kato: "Temperature dependence of giant magneto-resistance in PtMn and Fe_2O_3 based specular spin valves"J. Magn. Magn. Mat.. 240. 168-170 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Takahashi: "Exchange anisotropy in NiFe/NiO/CoPt trilayers"Surface Science. Vol.493. 731-736 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] N.Hashida: "Simulation of thermomagnetic recording using extended Huth's equation"J.Magn.Soc.Jpn.. vol.25. 303-306 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Sugihara: "Structure and magnetic properties of epitaxial CrPt_3 and Cr_<0.8>Mn_<0.2>Pt_3 alloy films"J.Magn.Soc.Jpn.. vol.25. 234-237 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] T.Kato: "Magnetic properties of polycrystalline and epitaxial Cr_<1-x>Mn_xPt_3 alloy films"IEEE Trans.Magn.. Vol.37. 2414-2416 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] P.Fischer: "Element-specific Imaging of Magnetic Domains at 25 nm Spatial Resolution Using Soft X-ray Microscopy"Rev.Sci.Instrum. Vol.72,No.5. 2322-2324 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] N.Katagi: "Observation of Thermomagnetically Recorded Magnetic Domains in TbFeCo Films with Soft X-Ray Microscopy"Jpn.J.Appl.Phys.. vol.40 No.4B. L380-L382 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Takahashi: "Influence of Groove Shape on Rear Expansion Detection Readout"Jpn.J.Appl.Phys.. vol.40 No.3B. 1590-1591 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] P.Fischer: "High Resolution Imaging of Magnetic Domains with Magnetic Soft X-ray Microscopy"J.Magn.Soc.Jpn.. vol.25,No3-2. 186-191 (2001)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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