ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
33.57
Showing 1-17 articles out of 17 articles from the selected issue
  • Type: Cover
    Pages Cover1-
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (13K)
  • Type: Index
    Pages Toc1-
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (65K)
  • Masukazu IGARASHI, Yoshio SUZUKI, Yo SATO
    Type: Article
    Session ID: MMS2009-72
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The mechanism of spin torque oscillation or magnetization rotation in a field generation layer (FGL) for Microwave Assisted Magnetic Recording (MAMR) was investigated by analytical way. Using a single spin model, following results were obtained. 1) The oscillation frequency at the maximum magnetic field output is decided by the vertical component of the magnetic field from the main pole. 2) When there is a strong external magnetic field, it is difficult to restrain the FGL magnetization in the plane of FGL and the oscillation becomes unstable. 3) It can be expected that the spin torque oscillator with planar magnetization material is appropriate for MAMR. 4) The spin torque oscillator that has FGL using a planar magnetization material is useful for the MAMR.
    Download PDF (693K)
  • Naoki HONDA, Tatsuya KOMUKAI
    Type: Article
    Session ID: MMS2009-73
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Bit patterned media technology is expected to realize high areal density. Distribution of the magnetic switching field, however, becomes broad due to increased magnetostatic interaction between the dots when the areal density is increased. While the distribution could be reduced using inclined anisotropy of the dots. This reducing mechanism was analyzed using a simple magnetic dipole model. It was found that the absolute value of the interaction field is increased but the effect of the interaction field on the switching field is reduced when the inclination of the anisotropy axis from the film normal becomes large. Inclined anisotropy is expected to serve large inclination in the adjacent magnetization when a dot is switching.
    Download PDF (765K)
  • Hajime AOI, Hideki SAGA, Ryosuke TATSUNO, Kazuki SHIRAHATA, Kaname MIT ...
    Type: Article
    Session ID: MMS2009-74
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Basic read-write characteristics of bit-patterned media (BPM) were empirically investigated. For this experiments, sample BPM employing hard/soft-stacked recording layer (Exchange-Coupled Composite; ECC structure) were prepared and measured utilizing static tester in contact recording mode. It was revealed that effective magnetic coupling between hard layer and soft layer is very important to reduce the recording field intensity utilizing hard-soft stack effect.
    Download PDF (1090K)
  • Hisashi OSAWA, Masayuki KAWAE, Yoshihiro OKAMOTO, Yasuaki NAKAMURA, Hi ...
    Type: Article
    Session ID: MMS2009-75
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    The neural network equalizer (NNE) for the partial response maximum likelihood (PRML) system with a post-processor in perpendicular magnetic recording is studied. First, a design method of NNE is proposed for suppressing a high-level noise at the discrimination point. In our method, the NNE is designed by using a hybrid distributed genetic algorithm with a combination of a distributed genetic algorithm and a simulated annealing algorithm, and the suppression of a high-level noise and the simplification of NNE are attained. Then, the bit error rate performance of PR1ML system with a post-processor using the NNE is obtained and compared with those using a conventional NNE without a noise suppressing function and a conventional transversal filter as an equalizer. The results show that the performance of the proposed system is superior to those of conventional systems.
    Download PDF (927K)
  • Nobumasa NISHIYAMA
    Type: Article
    Session ID: MMS2009-76
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    High data rate of a HDD follows on progressing, and the error rate degradation by the external signal is becoming large. Its attention was paid to the interference signal by the EM wave or conductive signals in order to clarify the cause of invasion of the induced current inside DE. The causes are. (1) The impedance between cover and base is high, and since the impedance between the cover and base through the spindle inside the DE is lower, then interference current flow an inside. (2) About the slot which consists of cover, base and screws, the slot resonance phenomenon by the electromagnetic wave arises. The high frequency current near the resonance frequency invade the inside of the DE. The measure shows below. A metal tape is stuck on the mid portion of a slot, it makes size small. Furthermore, a metal tape makes short-circuits between cover and base, and makes lower impedance between them. Invasion of external interference signals are deterred and a SER improvement can be realized..
    Download PDF (1059K)
  • Seiichi MITA
    Type: Article
    Session ID: MMS2009-77
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    We have proposed a novel method to reduce errors caused by inter-track interference (ITI) and inter-symbol interference (ISI) by iterative use both of an adaptive estimation for ITI and the log likelihood ratios obtained from a neighboring track signal. Under the condition of additive white Gaussian noise and a track shift of 20%, it is confirmed by simulation that proposed method can reduce bit errors at nearly the same bit error rate as that of no ITI.
    Download PDF (928K)
  • Kenta KASAI, Kohichi SAKANIWA
    Type: Article
    Session ID: MMS2009-78
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Recently, non-bibary LDPC codes over GF(2^m) attract much attention. Despite the considerable potential for error correction, non-binary LDPC codes suffer from huge decoding complexity and memory requirement. This report briefly reviews design and decoding schemes of non-binary LDPC codes.
    Download PDF (731K)
  • Yuri NUKAGA, Mitsuru OHTAKE, Osamu YABUHARA, Fumiyoshi KIRINO, Masaaki ...
    Type: Article
    Session ID: MMS2009-79
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Co epitaxial thin films were prepared on MgO substrates of (100), (110), and (111) planes by molecular beam epitaxy. The nucleation of Co crystal on MgO substrate varies depending on the substrate orientation and the substrate temperature. On MgO(100) substrates, Co(112^^-0) epitaxial bi-crystalline films with hcp structure are obtained at temperatures higher than 300℃, whereas a Co epitaxial film prepared at 100℃ includes fcc(100) crystal in addition to hcp(112^^-0) crystal. Co(110)_<fcc> single-crystal films with fcc structure are formed on MgO(110) substrates. Co films consisting of fcc(111) and hcp(0001) crystals epitaxially grow on MgO(111) substrates. With increasing the substrate temperature, the volume ratio of hcp(0001) crystal increases, whereas that of fcc(111) crystal decreases. High-resolution transmission electron microscopy shows that atomically sharp boundaries are formed between the Co films and the MgO substrates, where misfit dislocations are preferentially introduced in the films at the interfaces. The presence of such dislocations relieves the strain caused by the lattice mismatches between the films and the substrates.
    Download PDF (2727K)
  • Mitsuru OHTAKE, Takahiro TANAKA, Fumiyoshi KIRINO, Masaaki FUTAMOTO
    Type: Article
    Session ID: MMS2009-80
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Ni and NiFe epitaxial thin films were prepared on Au(100) single-crystal underlayers by molecular beam epitaxy. The structural and the magnetic properties were investigated. hcp-Ni and hcp-NiFe crystals are obtained at temperatures lower than 300℃ and 400℃, respectively. The both kinds of hcp crystals consist of two types of (112^^-0)_<hcp> domains whose c-axes are in plane and rotated around the film normal by 90° each other. The hcp crystals tend to transform into more stable fcc crystals during film growth process with increasing the substrate temperature. X-ray diffraction and high-resolution transmission electron microscopy show that the Ni and the NiFe films prepared at 100℃ consist primarily of hcp crystals. The saturation magnetization values of hcp-Ni and hcp-NiFe films are similar to those of bulk fcc-Ni and fcc-NiFe crystals. The in-plane magnetization properties of hcp-Ni and hcp-NiFe films are interpreted to be reflecting the magnetocrystalline anisotropies of bulk hcp crystals.
    Download PDF (1940K)
  • Kinya FUDANO, Yoshihisa NAKAMURA, Kiyoshi Yamakawa, Hiroaki Muraoka
    Type: Article
    Session ID: MMS2009-81
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    A high head field gradient is the most crucial criterion for a write head. A new approach with a grooved soft magnetic underlayer (SUL) structure was investigated for use with a single-pole planar writer. Cross-track grooves on the SUL surface improved the writing field gradient without degrading the field strength. In this study, a detailed analysis of the head field distributions and writing process with the heads and medium were performed using a finite-element method (FEM) computer simulation. The simulator was combined with a Stoner-Wohlfarth magnetization reversal model, in which head-medium magnetic interactions were incorporated by calculating the head and medium magnetization together as a 'self-consistent' system, designated as "SMART". A maximum gradient greater than 1000 Oe/nm was confirmed with the grooved SUL structure and the recorded magnetization distribution for the high gradient writing head field was calculated.
    Download PDF (980K)
  • Shuma Horiuchi, Shuhei Yoshida, Manabu YAMAMOTO
    Type: Article
    Session ID: MMS2009-82
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    In this paper, we propose a novel numerical model for radical photopolymerization. In this model, elementary reactions such as initiation, propagation, termination are considered and it is assumed that each component in the material diffuse each other. We have analyzed diffraction characteristics of radical photopolymer based on this interdiffusion model with beam propagation method. Moreover, we have also performed experiment for hologram recording and evaluated the diffraction characteristics of photopolymer media. By fitting numerical results with experimental results using by Levenberg-Marquardt method, media parameters such as reaction rate and diffusion coefficient can be estimated. We have confirmed that interdiffusion model is efficiently and it can reproduce experimental results. In this study, it has been clarified that how these media parameters affect diffraction characteristics.
    Download PDF (654K)
  • Yo Kondo, Yosuke Takahata, Shuhei Yoshida, Manabu Yamamoto
    Type: Article
    Session ID: MMS2009-83
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    In Holographic Data Storage with multiplexed recording, the optical system aberration, medium shrinkage or cross-talk noise cause increase of bit error rate. Therefore, in this paper, we applied FIR equalizer to reconstructed images for the improvement signal quality. We also studied the effect of FIR filter for various modulation codes in off-axis recording system.
    Download PDF (657K)
  • Type: Appendix
    Pages App1-
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (77K)
  • Type: Appendix
    Pages App2-
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (77K)
  • Type: Appendix
    Pages App3-
    Published: December 10, 2009
    Released: September 20, 2017
    CONFERENCE PROCEEDINGS FREE ACCESS
    Download PDF (77K)
feedback
Top