ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
32.41
Showing 1-16 articles out of 16 articles from the selected issue
  • Type: Cover
    Pages Cover1-
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Type: Index
    Pages Toc1-
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Yuji KONDO, Takashi CHIBA, Jun ARIAKE, Kaori TAGUCHI, Motohiro SUZUKI, ...
    Type: Article
    Session ID: MMS2008-48
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We fabricated Co-Pt magnetic dot arrays using an electron beam writing and a low-energy ion etching in order to prevent from the deterioration of the magnetic properties. By comparing the results of X-ray magnetic circular dichroism measurement and micro magnetic simulation, it was found that the etching using low-energy ions cause little damage on not only the magnetization but also the anisotropy field. These results demonstrate the effectiveness of the etching using low-energy ions for realization of bit-patterned media with an areal density of 1 Tbit/in^2. Furthermore, the magnetic isolation between the dots in the magnetic dot array with the dot pitch of 30 nm was confirmed by SEM and MFM observations.
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  • Mitsuru OHTAKE, Yuri NUKAGA, Fumiyoshi KIRINO, Masaaki FUTAMOTO
    Type: Article
    Session ID: MMS2008-49
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    SmCo_5(0001) epitaxial thin films are obtained on Al_2O_3(0001) single-crystal substrates employing Cu(111) single-crystal underlayers, whereas Sm-Co amorphous phase grows on Ru(0001) and Co(0001) underlayers. The SmCo_5 epitaxial layer formed directly on Cu underlayer consists of two types of domains whose orientations are rotated around the film normal by 30 degrees each other. By introducing a thin seed layer on the Cu underlayer, an SmCo_5(0001) single-crystal film is successfully prepared. Cu atoms diffused from the underlayer substitute a part of the Co sites in the SmCo_5 structure, and an alloy compound of Sm(Co,Cu)_5 phase is formed. The Cu atom diffusion plays an important role in assisting the formation of SmCo_5(0001) epitaxial thin film.
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  • Tsutomu NISHIYAMA, Mitsuru OHTAKE, Fumiyoshi KIRINO, Masaaki FUTAMOTO
    Type: Article
    Session ID: MMS2008-50
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Ni thin films were prepared on fcc(111) single-crystal underlayers by UHV-MBE. The effects of underlayer and substrate temperature on the formation of Ni(111) epitaxial thin films were investigated. Ni(111) epitaxial thin films were obtained on Cu(111)_<fcc>, Au(111)_<fcc>, and Ag(111)_<fcc> underlayers. The lattice strain of Ni epitaxial thin film is influenced by the underlayer and the substrate temperature. Ni thin films formed on Cu and Au underlayers are strained due to diffusion of underlayer atoms into the Ni films. The atomic diffusion is enhanced with increasing the substrate temperature. Ni thin film formed on Ag underlayer involves reduced strain. During Ni film deposition on Ag underlayer, parts of Ag atoms segregate into the Ni film forming a complicated film structure consisting of Ni(111)_<fcc> and Ag(111)_<fcc> phases.
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  • Kenji TABUCHI, Takahiro TANAKA, Kouhei SHIKADA, Mitsuru OHTAKE, Fumiyo ...
    Type: Article
    Session ID: MMS2008-51
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Fe thin films were prepared on SrTiO_3(100), SrTiO_3(110), SrTiO_3(111) single-crystal substrates by UHV-MBE. The film growth structure and the magnetic properties were investigated. Fe epitaxial thin films with bcc structure were obtained on these SrTiO_3 substrates at elevated temperatures. The nucleation of bcc-Fe crystal on respective SrTiO_3 substrates varies depending on the substrate plane and the substrate temperature. The nucleation and growth of bcc-Fe film on SrTiO_3 substrates seems to be influenced by the strain and/or stress existing at the Fe/SrTiO_3 interface. The in-plane magnetic anisotropy measured for these epitaxial thin films reflects the magnetocrystalline anisotropy of bulk bcc-Fe crystal.
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  • Kouhei SHIKADA, Tsutomu NISHIYAMA, Mitsuru OHTAKE, Fumiyoshi KIRINO, M ...
    Type: Article
    Session ID: MMS2008-52
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    FeCo epitaxial films were prepared on MgO and Al_2O_3 single-crystal substrates by UHV-MBE. FeCo thin films with (100), (211), and (110) planes parallel to the substrate surface grow on MgO(100), MgO(110), and MgO(111) substrates, respectively. In the cross-sectional TEM analysis, atomically sharp boundaries are recognized between the FeCo thin films and the MgO substrates where misfit dislocations are introduced in the FeCo thin films. Misfit dislocations are observed approximately every 9 nm and 1.4 nm in FeCo thin film for the FeCo/MgO(100) and the FeCo/MgO(110) samples, respectively. The periodical introduction of misfit dislocations decreases the lattice misfits existing at the FeCo/MgO interfaces. An FeCo(110)_<bcc> film grows epitaxially on Al_2O_3(0001) substrate with the two type variants, Nishiyama-Wasserman and Kurdjumov-Sachs relationships, whereas multiple types of crystal nucleation are observed on Al_2O_3(1120) substrate. The magnetic anisotropies of these epitaxial films are interpreted to be reflecting the magnetocrystalline anisotropy of bulk FeCo alloy crystal.
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  • Hitoshi SAITO, Tasuku MIYAZAWA, Genta EGAWA, Shunji ISHIO, Satoru YOSH ...
    Type: Article
    Session ID: MMS2008-53
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We developed a new imaging method for detection of in-plane magnetic field gradient with high resolution in MFM. This method can detect the in-plane magnetic field gradient of arbitrary direction by changing the scanning direction of cantilever. On the same scan, out-of-plane magnetic field gradient can be measured simultaneously by conventional phase detection method. Therefore, this imaging method is useful to estimate the transition of recording bits in perpendicular magnetic recording media. We will present the imaging results for perpendicular magnetic recording media with utilizing the new method.
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  • Hiroyuki Nakagawa, Ryoko Araki, Reiko Arai, Hiroaki Nemoto, Kiwamu Tan ...
    Type: Article
    Session ID: MMS2008-54
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We have introduced structural and magnetic gradations into the granular layer so as to be a well-isolated structure with Si-oxide and Cr-oxide segregated to the grain boundary at the bottom portion and a less-isolated structure, low Ms, and low Ku with Cr remaining in the core at the top portion. These gradations enable us to use thinner cap and promote incoherent magnetization reversal, resulting in the reduction of magnetic cluster size, switching field, and its distribution. The graded media with shallower Hcr angular dependence and small magnetic cluster size shows better OW, SNR, and ATI performance.
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  • Hisashi OSAWA, Masaya HINO, Yoshihiro OKAMOTO, Yasuaki NAKAMURA, Hiroa ...
    Type: Article
    Session ID: MMS2008-55
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The neural network equalization for a generalized partial response maximum likelihood (GPRML) system in a perpendicular magnetic recording channel with thermal decay is studied. First, a designing method of the simplified neural network equalizer (NNE) with the noise whitening function is proposed. The method is based on thinning out of the connections of NNE which is obtained by the alternately iterative learning using a hybrid genetic algorithm and a Levinson-Durbin algorithm. Then, the bit error rate degradation performances with the elapsed time for the GPR1ML and PR1ML systems using this simplifed NNE (GPR1ML-NNE and PR1ML-NNE) are obtained and compared with that for the GPR1ML system using a conventional transversal filter as an equalizer (GPR1ML-TF). It is clarified that both GPR1ML-NNE and PR1ML-NNE show the excellent performance compared to that of GPR1ML-TF.
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  • Yoshihiro OKAMOTO, Taku BUSHISUE, Yasuaki NAKAMURA, Hisashi OSAWA, Hir ...
    Type: Article
    Session ID: MMS2008-56
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    A method to make the R/W waveform sequence with required proportion of noise power and SNR is studied in this report. In addition, we study whether the R/W waveform sequence made by our proposed method can be used for evaluation of signal processing systems. The results show that the proposed method can make the R/W waveform sequence with required proportion of noise power and SNR by extracting noise sequence from the original R/W wavefrom sequence and adjusting it, and the R/W waveform sequence can be used for evaluation of signal processing system.
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  • K. Hirata, J. J. Kim, Y. Ishida, H. Kasai, D. Shindo, M. Takahashi, A. ...
    Type: Article
    Session ID: MMS2008-57
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Observation of in-plane domain structure of writer pole for perpendicular recording head was performed by electron holography in order to investigate the cause of pole erasure concerned to the instability of domain state. As a result, it was found that the stability of domain structure relates to the domain wall trapping, and the pole erasure can be suppressed by the stable domain structures.
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  • Maki Maeda, Hiroki Kobayashi, Junzo Toda, Yuichi Sato, Shin Eguchi
    Type: Article
    Session ID: MMS2008-58
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    For a perpendicular writer, it is necessary to reduce the pole tip remanence as well as to improve the writing efficiency. To improve the writing efficiency for a narrow core width design, a tapered main pole geometry is proposed. We simulated the head remanence of the tapered main pole head with a micromagnetic model. To reduce the head pole tip remanence, a single magnetic domain structure forming a vortex state from the pole tip (ABS) to the tapered region is preferred. A tapered main pole structure with the trailing gap depth (TGD) below 30 nm and the tapered angle (TGθ) equal to about 30 degrees effectively improved the writing efficiency. This is achieved with a higher head field value of more than 1.3 times of the conventional structure. Moreover, the pole tip remanence is reduced to a value closer to the conventional structure.
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  • Type: Appendix
    Pages App1-
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Type: Appendix
    Pages App2-
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (78K)
  • Type: Appendix
    Pages App3-
    Published: October 09, 2008
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
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