Journal of the Magnetics Society of Japan
Online ISSN : 1880-4004
Print ISSN : 0285-0192
ISSN-L : 0285-0192
Search
Advanced search
OR
Browse
Search
Volume 21, Issue S_1_PMRS_96
Displaying 1-39 of 39 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • Nanostructure and Co-rich regions of Plasma-free sputtered Co-Cr films
    Masahiko Naoe, Sadao Kadokura
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_1-4
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_1
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      150nm thick Co-20at%Cr films with c-axis oriented hcp structure prepared by a new facing targets sputtering coater were evaluated on nanostructure of initial-, middle-, and surface-layers. 5-10 nm sizes Co-rich regions separeted by 3-10 sized Cr-rich once were confirmed to be distributed within 10-30 nm sized crystalites and across crystallite boundaries on all specimens of any layers.
    View full abstract
    Download PDF (1105K)
  • Evaluation of spinodal decomposition process on sputtered Co-Cr films by heat flux method
    Sadao Kadokura, Masahiko Naoe
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_5-9
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_5
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Spinodal decomposition characteristics of Co-Cr films with highly oriented c-axis crystallites of hcp phase were evaluated from heat flux measurement of adatoms as well as plasma bombardment on deposition plane. Distribution and nano-size of Co-rich and Cr-rich regions from spinodal decomposition may be controlled under plasma free conditions with highly energized adatoms and also quantified from heat flux measurement.
    View full abstract
    Download PDF (1007K)
  • Magnetic Coupling between Grains in Post-annealed CoPt-based Alloy Thin Film Improved by Cr Addition
    Ryoichi Mukai, Kaznori Yamanaka, Mitsumasa Oshiki
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_10-14
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_10
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Segregation of Cr at the grain boundaries of post annealed CoPt and CoCrPt alloy/Cr thin film systems has been investigated for decreasing magnetic coupling between grains in magnetic thin film. It has been found that Cr is diffused from the Cr underlayer into the CoPt magnetic layer during this post annealing, resulting segregation at the grain boundaries. In addition to the Cr diffusion from underlayer, Cr is diffused from magnetic grains in CoCrPt/Cr structure case. Therefore, the addition of Cr to as-deposited Co-based magnetic film causes increase of the segregation. In the case of 20 nm-thick CoCrPt/50 nm-thick Cr system, the coercivity of maximum value 4.6 kOe and Hc/Hkgrain of maximum value 0.46 were obtained after post annealing at 460°C.
    View full abstract
    Download PDF (1261K)
  • Optimization of Underlayer, Ta Addition, and Gas Pressure for Co-Cr Thin Film
    Kohki Noda, Takashi Kawanabe, Masahiko Naoe
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_15-18
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_15
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      The magnetic properties of Iongitudinal magnetic recording media with Co-Cr alloy films deposited by facing targets sputtering (FTS) were investigated. These properties are dependent on sputtering conditions such as the argon gas pressure, substrate temperature, and alloy composition of the underlayer of the magnetic film. In this study, the magnetic properties of Cr, Cr-Ta, and Cr-Co underlayers were analyzed in relation to the Ar gas pressure and substrate temperature. The magnetic properties of Co-C-Ta/Cr bi-layered films were also studies to determine the advantage of Ta addition. Consequently, the dependence of the magnetic properties on the sputtering conditions was systematically clarified for practical use in fabricating magnetic recording disks.
    View full abstract
    Download PDF (930K)
  • Magnetization buckling in perpendicular magnetic films with columnar structure
    Y. Ishii, S. Suzuki
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_19-23
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_19
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      The magnetization buckling mode is studied in a perpendicular magnetic film with columnar structure. The calculated nucleation field HN of the buckling mode is compared with HN of the curling and coherent rotation modes. It is found that the buckling occurs only in the restricted condition of the diameter and axial ratio of the crystallites constituting the film. In addition HN of the buckling mode is very close to HN of the coherent rotation mode. Therefore the buckling mode is not required to be taken in account in a perpendicular magnetic film with columnar structure.
    View full abstract
    Download PDF (906K)
  • Look Foward to Video Storage System using Hard Disk Drive
    Hideo Ohshima
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_38-43
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_38
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      This paper reports on the concept and configuration of production of multimedia programs at broadcasting station. The new video hard disk system for real-time recording and playing back of high quality digital video signals, is important in the nonlinear video editing systems and on-line transmission systems. A new hard disk interface device suitable for transferring digital video signals is introduced.
    View full abstract
    Download PDF (940K)
  • Perpendicular Magentic Recording using Single-pole Head
    - Current Status and Problems -
    Yoshihisa NAKAMURA
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_44-53
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_44
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Perpendicular magnetic recording using a single-pole head and a double-layered medium is still keeping the champion data on the writable and readable highest linear bit densities over 500 kFCl. In this paper, the feature of perpendicular magnetic reording and the design principle of the heads and media, the hot data of the recording characteristics, the problems for developement, and the future of magnetic reording are decribed.
    View full abstract
    Download PDF (1427K)
  • Perpendicular Magnetic Recording Medium Optimized for an MR Head
    Y. Ikeda, Y. Sonobe, H. Uchida, T. Toyooka
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_54-59
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_54
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      We optimized a perpendicular magnetic recording medium for use with a merged MR head designed for longitudinal media. The dual-layer perpendicular medium with a low-Hc underlayer, has problems in write operation and MR bias current dependence of signal distortion. The single-layer Co-Cr perpendicular medium has similar MR bias current dependence of the signal amplitude and the signal distortion to the longitudinal medium. The Cr content increase from conventional 22% to 28% results the signal to noise ratio increase. The Ti underlayer contributes to increase the recording resolution but not to decrease the medium noise. The Cr-rich Co-Cr perpendicular medium with large thickness and low Ms value is expected to be used with the future high-sensitivity MR head for realizing high-density recording of more than 10 Gbits/inch2.
    View full abstract
    Download PDF (1010K)
  • A View on Longitudinal Magnetic Recording
    Katsumichi Tagami, Toshiyuki Okumura
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_60-64
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_60
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Subjects for recording densities of 10Gbt/in2 - 30Gb/in2 are discussed, for longitudinal and perpendicular recording. Read-write specifications are estimated for their high recording densities. Reproducing outputs above 1mVpp/μm for magnetic heads are required. Correlation between magnetic media properties and recording densities are calculated for 10 - 30 Gb/in2 densities. Noise characteristics subjects and thermal instabilities are discussed for longitudinal recording media and perpendicular recording media.
    View full abstract
    Download PDF (900K)
  • Fabrication of Ba-Ferrite Sputtered Films with Low Temperature Annealing and Their Magnetic Properties
    K. Kakizaki, N. Hiratsuka
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_65-69
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_65
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Barium ferrite films were prepared by rf diode sputtering on a quartz substrate at room temperature. Because the as-deposited films had poor crystallization, the films were post-annealed at various temperatures in air to induce crystallization. In films with high iron concentrations (Fe/Ba>15), the crystallization temperature of the BaFe12O19 phase was about 700°C. On the other hand, in films with stoichiometry composition and high barium concentrations (Fe/Ba>8.6), the crystallization temperature of the BaFe12O19 phase was about 650°C, which was lower than that of films with high iron concentrations. Because in high iron concentration films spinel phase was quickly crystallized at low temperature, it was difficult to form hexagonal phase.
    View full abstract
    Download PDF (966K)
  • Deposition of c-axis oriented Ba ferrite thin films by atomic layer deposition method for high density magnetic recording media
    H. Shimizu, H. Shinozaki, Y. Hoshi, K. Kato, F. Kaneko, H. Ikawa
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_70-73
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_70
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      In this study, c-axis oriented Ba-ferrite (BaM:BaFe12O19) films about thick 115 nm thick were deposited using an alternate atomic layer deposition method. R layer (BaO·3Fe2O3 layer) thicknesses from 4.6 to 5.9 Å and S layer (spinel: Fe3O4 layer) thicknesses from 4.6 to 5.4 Å deposited 100 times alternately by sputtering at a substrate temperature between 580 °C and 655 °C in an atmosphere of 90%Ar and 10%O2. Before the BaM films were deposited, a ZnO underlayer 15 nm thick was deposited on the thermally oxidized silicon wafer substrate. A strict control of the thickness of R layer and S layer was necessary to obtain a single hexagonal BaM phase. A single-phase BaM film obtained by alternate deposition of 6.9 Å R layers and 4.6 Å S layers at 630 °C had excellent c-axis orientation ( Δθ50 = 2.4° ). Typical magnetic properties of the film were as follows: saturation magnetization Ms=200 emu/cc, perpendicular coercivity Hc⊥ = 3.1 kOe and in-plane coercivity Hc//=0.17 kOe.
    View full abstract
    Download PDF (934K)
  • A New Quantitative Technique for Characterizing Nonlinearites in an MR head
    Yutaka Okazaki
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_74-77
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_74
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      A new simple calculation technique using a pseudo-random sequence is proposed to characterize MR head nonlinearites. The method makes it possible to extract the MR transfer function from a read back signal which includes nonlinearites caused in both recording and reproducing processes.
      A nonlinear-canceller based on this result will be also discussed, after confirming the accuracy of the method.
    View full abstract
    Download PDF (832K)
  • Neural Network Equalization of Nonlinear Channel with Partial Erasure
    Kohei WAKAMIYA, Hisashi OSAWA, Yoshihiro OKAMOTO, Hidetoshi SAITO
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_78-82
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_78
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      A neural network equalization of nonlinear channel with partial erasure is studied. First, a model of the recording/reproducing channel with partial erasure and a neural network equalizer are described. Then, the bit-error rate for PR4ML system is obtained by computer simulation and the performance is compared with that of the convention al Nyquist equalization. The results show that the error rate peformance of neural network equalization is better than that of Nyquist equalization.
    View full abstract
    Download PDF (916K)
  • Neural Network Equalization for Nonlinear Distortion in MR Head
    Kohei WAKAMIYA, Hisashi OSAWA, Yoshihiro OKAMOTO, Hidetoshi SAITO
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_83-86
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_83
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      A neural network equalization for nonlinear distortion in magnetoresistive(MR) head is studied. First, a model of the recording/reproducing channel with MR head and neural network equalizer is described. Then, the bit-error rate(BER) for PR4ML system is obtained by computer simulation and the performance is compared with that of the conventional transversal filter equalization. It is shown that at a BER of 10-4, the neural network equalization yields about 4.2dB gain over the transversal filter equalization.
    View full abstract
    Download PDF (837K)
  • Error Rate Improvement of PRML System with ISI Canceller for (1,7) RLL Code
    Yoshihiro OKAMOTO, Harumitsu MIYASHITA, Hidetoshi SAITO, Hisashi OSAWA
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_87-90
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_87
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      A method to improve the error rate performance of PRML systems with an Inter-symbol Interference (ISI) canceller having a tentative sequence detector is presented. The new system adopts a combination of a minimum phase noise whitening matched filter and a Viterbi detector with a path feedback scheme as a tentative detector. The result obtained by computer simulation shows that at a bit-error rate of 10-4, the proposed systems improves the SNR by about 6.3 dB compared with the conventional EPR4ML system without an ISI canceller.
    View full abstract
    Download PDF (936K)
  • Flying and R/W characteristics of low flying single pole head for PMR
    A. Takayama, X. Ye, S. Ito, T. Sakurai, K. Honda
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_132-135
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_132
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      For perpendicular magnetic recording (PMR) system, low flying head is necessary in order to get optimum performances. In this study we designed low flying slider called "Y-slider" whose flying height was 25nm at 10 m/s disk velocity. We also fabricated a thin film magnetic head for PMR by combination of low flying slider and a single pole head in which FeZrN high Bsat film(Bsat=2T) was used as a main pole. Electrical performances of the head obtained were; TAA= 200 nVp-p/μm·m/s·T at 15kFCI, overwrite value= -41dB with 2580Oe Hc 50nm thick medium, and the maximum recording density=350kFCI by MFM observation.
    View full abstract
    Download PDF (968K)
  • Optimum Write Head Structure for Perpendicular Magnetic Recording Focused on the Write Field
    Yukiya SHIMIZU, Syuji NISHIDA, Hiroshi YAMADA, Hiroaki MURAOKA, Yoshih ...
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_136-139
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_136
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      The optimum structure of a recording head for a double-layer perpendicular medium has been studied by calculating the head field and the stationary recorded magnetization with a magnetic recording simulation program. The perpendicular field gradient of the thin film ring head is the same shape as that of the Single Pole Type (SPT) head. However, because of the magnetic saturation of the medium under-layer, the field distribution of the thin film ring head changes drastically with the change of write current. A wider gap length reduces this change of the head field, therefore the wide gap thin film ring head is able to be used with a double-layer perpendicular medium. It is confirmed that the thin film coil type SPT head reduces the influence of the magnetic saturation of the medium under-layer and writes a sharp transition.
    View full abstract
    Download PDF (924K)
  • Lubricant Design for In-Contact HDI Systems
    Masahiro Yanagisawa, Akinobu Sato, Ken Ajiki
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_140-143
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_140
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      In-conatct recording systems are expected for magnetic disk derives with an ultra-high recording density. Design concept of lubricant systems for the in-contact systems is much different from that for flying HDI systems. Other than wear performances, lubricants with high surface energies suppressed the bouncing of contact sliders. Specifically, the bouncing height of 3nm was obtained by the combination of 30% contact sliders and MPBT lubricants. It was found that wear performance of MPBT was ten times larger than that of PFPE diol lubricant.
    View full abstract
    Download PDF (963K)
  • High Density Magnetic Recording by Using Thin Film Tapes
    T. Ishida, R. Sugita, K. Tohma, K. Yoshimoto
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_144-148
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_144
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      As the most promising candidate for future high density tape storage media, Co-O thin film tapes have been developed with a vacuum evaporation method. The tapes are found to be composed of CoO and hcp Co, well oriented and highly uniaxial along the columnar grains obliquely grown to the film normal direction. Experimental results of read/write characteristics with ring-type heads, as well as MFM analyses, suggest that the tapes are endowed with resolution potential high enough to attain Gb/in2 order of areal recording density.
    View full abstract
    Download PDF (922K)
  • Preparation and recording characteristics of Co-γFe2O3 high density magnetic recording media
    T. Doi, K. Tamari, T. Andou, S. Yamamoto, H. Kurisu, M. Matsuura
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_149-153
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_149
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      We have investigated the preparation process and the recording characteristics of Co-γFe2O3 perpendicular magnetic recording media obtained by annealing the sputtered CoO-Fe3O4 films on the sputtered NiO underlayer. The NiO and CoO-Fe3O4 films were deposited at the rate of 520 nm/min and 130 nm/min, respectively. by DC magnetron sputtering. Moderately <100>-oriented Co-γFe2O3 media with intermediate perpendicular anisotropy ( Ku ≒ 6.0×105 erg/cm3 ) were prepared with a wide range of oxygen partial pressure used in deposition of NiO and CoO-Fe3O4 films. These media showed a superior high density recording performance which was comparable to that of highly <100>-oriented Co-γFe2O3 media with large perpendicular anisotropy.
    View full abstract
    Download PDF (1011K)
  • Noise characteristics of Co-γFe2O3 perpendicular magnetic recording media
    T. Andou, S. Yamamoto, H. Kurisu, M. Matsuura, T. Doi, K. Tamari
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_154-158
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_154
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      The Co-γFe2O3 perpendicular recording thin film disks were prepared by annealing a CoO-Fe3O4 single layer deposited on a NiO underlayer in air in the temperature range from 260 °C to 350°C. Noise characteristics of the Co-γFe2O3 disks were measured using a MIG-type ring head. From a DC reverse erase noise measurement and a measurement of recording density dependence of medium noise, it was found that the Co-γFe2O3 disks show noise characteristics which is often seen in thin film media. The Co-γFe2O3 disks show the higher Sp-p/Nm,rms than various longitudinal recording media now on the market at high recording densities over 40 kFRPI.
    View full abstract
    Download PDF (980K)
  • High density recording on Ba-Ferrite flexible disks using small gap length MIG head
    Naoki Honda, Takashi Komakine, Kazuhiro Ouchi
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_159-162
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_159
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      Recording properties of recently developed Ba-Ferrite flexible media with perpendicular anisotropy were evaluated in contrast with a conventional ZIP type metal medium by using narrow gap MIG head. The output, D50 and medium noise increased as SQ⊥ of the media became large. The achieved highest D50 was 180 kfrpi. Spp/Nrms was evaluated as 33 dB which was higher than the metal medium by 8 dB at 100 kfrpi for 6μm track width. Thus the areal density of more than 300 Mb/in2 would be expected for the system.
    View full abstract
    Download PDF (879K)
  • The Effect of Head-Medium Spacing for Ring-Type Head/Perpendicular-Longitudinal Composite Medium System
    Y. Kurokawa, T. Onoue, N. Miyamoto, T. Homma, T. Osaka
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_163-168
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_163
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      The effect of head-medium spacing on recording characteristics of perpendicular-longitudinal composite medium was investigated by using ring-type head. At lower density region, the spacing loss of composite medium is smaller than that of perpendicular single-layered (SL) medium. The composite medium with 0.05μm spacing layer shows reproduced voltage at higher density region than the SL medium with the same spacing. However, the spacing loss factor, which indicates the dependence of spacing loss on recording density, of composite medium is larger than that of perpendicular SL. Thus, nevertheless, the effect of spacing is suppressed with composite medium system than the perpendicular SL system, the optimization of head and medium parameters is necessary. Moreover, to clarify the effect of spacing on recording performance, it is necessary to analyze the recording mechanism of composite medium more in detail.
    View full abstract
    Download PDF (1062K)
  • Recording and noise properties of perpendicular media for ring heed
    Satoshi YANASE, Lianjun WU, Naoki HONDA, Kazuhiro OUCHI
    1997 Volume 21 Issue S_1_PMRS_96 Pages S1_169-172
    Published: 1997
    Released on J-STAGE: December 15, 2011
    DOIhttps://doi.org/10.3379/jmsjmag.21.S1_169
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
      We investigated the recording and noise properties for Co-Cr alloy single layer and Co/Pd multi layer media. Reproduced voltages increase with increasing δ·Mr for both media. DC erase noise of the media is related with δ·Ms·(1-SQ). Noise level of Co/Pd medium with large domain is larger than that with small domain, even the SQ is the same. Large SQ and small magnetic grains are required to obtain low noise media.
    View full abstract
    Download PDF (941K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top