日本応用磁気学会誌
Online ISSN : 1880-4004
Print ISSN : 0285-0192
ISSN-L : 0285-0192
18 巻 , S_1_PMRC_94_1 号
選択された号の論文の137件中1~50を表示しています
Keynote Address
Microstructure and Micromagnetics
  • Shin'ichi KITAHATA, Mikio KISHIMOTO
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_3-6
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Composite Ba-ferrite particles containing α-Fe were made by reducing Co-Ti-Sn substituted Ba-ferrite platelet particles in hydrogen gas. The crystal structure of Ba-ferrite is represented as the stacking of S and R layer, and the α-Fe in the composite Ba-ferrite particles was considered to be introduced primarily in the S layer in the Ba-ferrite hexagonal structure. The (110) plane of the α-Fe was parallel to the c plane of the hexagonal structure. The magnetic easy direction of the particles inclined to the plane for the samples with saturation magnetization larger than 62emu/g. The remanent coercivity of the particles was increased by introducing the α-Fe in the particles. These results indicated that the prepared particles were the composite magnetic particles consisting of hard material (Ba-ferrite) and soft one (α-Fe) behaving like a exchange spring magnet.
  • Teruo KOHASHI, Hideo MATSUYAMA, Kazuyuki KOIKE, Harukazu MIYAMOTO
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_7-10
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      We have developed a spin rotator for obtaining magnetic domain images of three independent magnetization components with spin-polarized scanning electron microscopy (spin SEM). In spin SEM, the spin rotator is placed between a sample and a spin detector, and can rotate a polarization vector of secondary electrons by 90 degrees. Since the spin detector itself can detect only two independent polarization components, the rotation of polarization makes third-component detection possible. The rotator is a known crossed electric and magnetic field type. However, new hyperbolic-shaped magnet-pole-pieces and a pair of flat main electrodes with four pairs of additional electrodes make the rotator able to accommodate secondary electrons emitted from a wide area of the sample. The spin rotator has been successfully applied in detecting of the magnetization vector distribution of a recorded TbFeCo magneto-optical disk.
  • PAN Guo Hong, WANG Qin Tang, SUN Yun Xi, CAI Yi Kun, WU Qin Lan, YAN Y ...
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_11-14
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      The inter-relationships among microstructure, domain structure and film magnetism have been investigated for Co-Cr films with the Cr content range between 0-32 at%, using SEM, TEM, Lorentz TEM (LTEM), including acid selective etched replica TEM. It is found that: 1. Both particulate and continuous models exist, but films with good perpendicular magnetization have particulate microstructure. 2. The film perpendicular magnetization process is a gradual Cr segregation process to form various patterns of isolated single domain Co clusters as Cr increases in an optimum Cr region (∼17-24 Cr at%). 3. The single domains are larger than columns which consisted of crystallite bundles. 4. These crystallites will be the smallest units and might give a potential bit length limit of an order of 10-10 2 nm, if recording is possible.
  • Kannan M. KRISHNAN, Teruaki TAKEUCHI, Yoshiyuki HIRAYAMA, David M. DON ...
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_15-18
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Highly c-axis oriented, single crystal films of Co1-xCrx (0≤x‹0.3) have been grown epitaxially on mica substrates by e-beam evaporation. The orientation relationship is basically (00.1)mica || (00.1)underlayer || (00.1)Co, and [11.0]mica || [10.0]underlayer || [10.0]Co. Films grown on Ru underlayers have an average grain size of 50-80nm, negligibe fcc content and very narrow c-axis dispersions (Δθ∼0.7-1.5°). For Co films (x=0), the as-grown magnetization structure are mainly 180° domain walls with a uniform distribution of cross-ties for thinner samples (≤300 Å), whilst thicker (› 400Å) ones show stripe domains. These images were analysed in detail to measure the wall widths and associated energy densities for as-grown, remanent and ac-magnetised samples. As expected, the magnetic properties of these films are composition dependent. However, for any Cr concentration, these films exhibit the largest saturation magnetisation when compared with either sputtered or evaporated samples. This enhancement can be attributed to a nanometer-scale segregation of Cr, which in these samples, could be particularly aided by the diffusion on the close-packed planes of the films with very narrow c-axis dispersions. Preliminary x-ray microanalysis and NMR data support this interpretation.
  • Masao HIRASAKA, Sadao KADOKURA, Shigenobu SOBAJIMA
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_19-22
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      A Co-Cr film was prepared on polyethylene naphthalate (PEN) film using the Facing Targets Sputtering System. The microstructure of the Co-Cr film was observed using transmission electron microscopy (TEM). Although grain sizes of Co-Cr crystals were 10 nm in an initial stage of deposition, the grain sizes of the Co-Cr crystals grew to 30 nm in both middle layer and surface layer of Co-Cr films. A high resolution TEM image of the Co-Cr film showed that neither void nor amorphous region exists at the grain boundaries of the Co-Cr film. The segregated microstructure was also observed using the acid etching method. A TEM image of segregated structure showed that the magnetic and non-magnetic regions were clearly separated from each other in the crystal.
  • Isuke OUCHI, Ikuo NAKAI, Hironobu MAEDA
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_23-26
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Co-Cr films. together with Co, Cr and some other related alloy films, were investigated by X-ray absorption fine structures (XAFS) at K-edges of Co and Cr for better understanding of the local structures. Co-Cr films showed similar extended XAFS (EXAFS) at K-edge of Co as those of Co films but showed some differences in near edges structures (XANES). Among Co-Cr films showing or not showing chrysanthemum patterns, there have been found little differences, if any, in EXAFS and XANES at K-edges of Co so far.
  • Yasushi MAEDA, David J. ROGERS, Koji TAKEI
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_27-30
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Compositional separation (CS) in Co-Cr based alloy thin films, which produces fine Co-enriched regions within grains, is expected to provide a particulate type magnetic microstructure suitable for high density magnetic recording. Towards the goal of establishing a synthetic phase diagram for Co-Cr thin films we examined the change in composition of the Co-enriched component as a function of mean Cr content. Our results show that CS occurs in single phase hcp solid solution thin films for Cr contents ranging from 5 to 22 at% Cr. The miscibility gap for Cr in the Co-enriched phase seems to be around 2 at% Cr. CS was also observed to occur in fcc Co-Mn alloy films. These results suggest that the origin of CS may lie in magnetically induced phase separation.
Date Storage Systems and Related Technologies
  • Hal H. OTTESEN
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_31-36
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      This paper focuses on some of the newer servo technologies that have been added to the actuator servo control system in order to meet the higher track density requirements for future HDD. After a brief description of the basic digital actuator servo control system, the paper focuses on the use of elliptic filters to reduce the effects of mechanical resonance disturbances. Then a short discussion follows on the position sensor errors. A development of the governing equation for the total position error consisting of repeatable and non-repeatable error components is made. Feedforward control can be used to increase track density by reducing the repeatable position error. A brief discussion is given on the use of accelerometers to protect the HDD from unrecoverable data errors caused by external shocks and vibrations. A predictive write/read inhibit decision using fuzzy logic shows a way to relax the tracking requirements. Increasing the HDD track density to 25,000 tracks/inch requires a five fold increase in todays servo bandwidth. This can be accomplished by placing a rotary micromechanical actuator piggyback on the slider. Some thoughts around the use of piggyback actuators in HDDs are given.
  • Jiang-ling ZHANG, Na HELIAN, Xue-jun HU
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_37-40
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      To minimize the restriction of conventional servo method, a new method used graphics for head positioning have been investigated. This paper will describe the principals of graphical construction and encoding, servo demodulation, and performance evaluation of graphics, etc. Finally for verifying this method, a 4000 TPI track density trial device is introduced.
  • Satoru SEKO, Toru TAKEDA
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_41-44
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Acompensation method of write off track using piggy-backed 2gap head on hard disk drive isdiscussed. The read and write gap offset of piggy-backed 2gap head is fomulated, and the measurement method for 2 gap HDA is introduced. The residual tracking error after offset-compensation is analyzed. Finally, a linear interpolation compensation is proposed, and the theoretical residual error is estimated as less than 0.1 μm.
  • Hiroaki YADA, Takamichi YAMAKOSHI, Takafumi ARAI, Munekatsu FUKUYAMA
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_45-48
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      A track density simulation model for a discrete track medium and an MR/Inductive head was developed based on an iterative geometric signal-to-noise ratio calculation. Using this model, we optimized design parameters of discrete track media related to track density. Our model suggests that discrete track media can achieve higher track density than conventional continuous track media.
  • Herbert SCHEWE, Michael VIETH
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_49-52
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      In this paper a newly developed magnetic encoder system is presented that can detect absolute and incremental angular positions. The encoding is performed by combining a perpendicularly oriented code disk and a magnetoresistive read array that is placed at a distance of 50μm above the medium. Results of numerical calculations show the influence of track width and sensor height on the signal. A carrier-to-noise-ratio of 35 dB was achieved with a 400μm wide absolute code track and an appropriate barber-pole-type read sensor.
  • Vish JUMANI
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_53-58
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Customer requirements have guided the evolution and implementation of software and hardware computer data storage technologies. The concept of RAID originated with a group of researchers at the University of California at Berkeley (UCB). They were investigating the use of an array of small capacity, inexpensive personal computer direct access storage devices (DASD) managed by a special type of a controller, as an alternative to the single large expensive disk (SLED) subsystems more common on mainframe computers. The disk arrays can be configured differently to provide different levels of operational capabilities, each providing special advantages in reliability and data availability, speed and economy. Different configurations are referred to as different levels of RAID. Berkeley originally defined a basic set of RAID levels ranging from RAID, level 0 (RAID 0) through RAID, level 5 (RAID 5). The RAID technology vendors have since extended the RAID level domain by defining RAID 6 and beyond to accommodate additional functionality. Each RAID type has shown itself to be suitable for certain applications. The projected reduction in storage costs and facilities, $/GB and ft2/GB respectively, using the present RAID technology and its projected evolution are phenomenal.
Media - I
Recording Theories and Simulations
Invited Session - I
  • Yoshihisa NAKAMURA
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_161-170
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      Magnetic data storage possesses the potential for extremely high bit density exceeding 1 Tb/cm2 or about 10 Tb/inch2, which corresponds to storing each bit into each ferromagnetic fine particle composing a magnetic storage medium. We call this perpendicular spinic storage (PSS)' because this tremendous potential of extremely high bit density could only be established by perpendicularly magnetizing ferromagnetic particles, or parallel spin clusters, arranged systematically and oriented perpendicularly on a substrate. The possibility and the background of terabit PSS in magnetic storage technology are discussed from the viewpoint of theoretical considerations and the current situation in high density recording. To approach this tremendous possibility, main-pole thick width (MPTW) recording of several hundreds nanometer in width and dispersive writing and collective reading (DWCR) with a multiple-track head are proposed.
  • Harold HAMILTON
    1994 年 18 巻 S_1_PMRC_94_1 号 p. S1_171-178
    発行日: 1994年
    公開日: 2011/12/15
    ジャーナル オープンアクセス
      In recent years, efforts in the industry to reduce head/media spacing loss and increase areal recording density, for the most part, have been directed toward reducing the size and mass of air bearing sliders to enable very low flying height. An alternative to this strategy aims at operating ultra low mass heads in continuous sliding contact with the media. This paper, will summarize the progress that has been achieved at Censtor Corp. over the past several years in this latter approach to extending recording density, which is now being implemented in small form factor disk drive designs.
Heads - I
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