2007 Fiscal Year Final Research Report Summary
Composite magnetic films for optically assisted magnetic recording (rapid thermally annealed FePt crystalline grains/magneto optical recording film)
| Project/Area Number |
18560347
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electron device/Electronic equipment
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| Research Institution | Nihon University |
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Principal Investigator |
ITOH Akiyoshi Nihon University, College of Science and Technology, Professor (60059962)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAGAWA Katsuji Nihon University, College of Science and Technology, Professor (20221442)
OTSUKI Joe Nihon University, College of Science and Technology, Associate Professor (80233188)
TSUKAMOTO Arata Nihon University, College of Science and Technology, Assistant Professor (30318365)
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| Project Period (FY) |
2006 – 2007
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| Keywords | optically assisted magnetic recordeing / FePt / magnetic composite film / Rapid thermal annealing method / self-organizing / metoporous SiO_2 / nano-template / magnetic domain wall pinning |
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| Research Abstract |
In this study, we discussed the composite magnetic recording media, consisting of FePt grain under layer with TbFeCo continuous layer, as high density optically assisted recording media over 1 Tbit/in^2. Due to its high magnetic anisotropy K_u and the capability of forming small grains, FePt is a leading candidate for high density magnetic recording media that are preferable to overcome the thermal fluctuation of small magnetic grains. FePtX (X=Cu, Ni) prepared by Rapid Thermal Annealing (RTA). To increase areal packing density of FePtX grains, a SiO_2 Substrate having self-organized nano-pores was used as a nano-template. Main results were followings
1) Fabrication of nano-dent array substrate by self-assemble method
We succeeded to fabricate SiO_2 film having highly ordered nano-pores inside, and found that the dilution of a solvent with ethanol is effective to thinning the film thickness preparing by spin coring method.
2) Decrease of the Curie temperature of FePt by Cu or Ni doping
Substituting Cu or Ni for some of the Fe is expected to reduce the K_u i. e. Curie temperature T_c (FePt, T_c=500℃ at room temperature). We fabricated well isolated FePtX(X=Cu, Ni) particles by RTA, and confirmed the doping effect to reducing Curie temperature. Deferent content dependence was found in each element.
3) Micro-magnetic simulations of domain shape incomposite magnetic recording media
Simulated result of composite magnetic film consisting of FePt grains under layer and TbFeCo continuous layer shows tiny domain could be formed (domain diameter 22 nm at the TbFeCo surface). Even the spacing between each grain decreased less than the theoretical domain wall width, FePt particles act as domain pinning sites of TbFeCo layer.
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