ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
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25.62
Displaying 1-9 of 9 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    Pages Cover1-
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_Cover1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    Pages Toc1-
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_Toc1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Thermal Stability of Co-containing Ferrite Thin-Film Media Prepared by Reactive ECR Sputtering Method
    Kei HIRATA, Setsuo YAMAMOTO, Hiroki KURISU, Mitsuru MATSUURA, Terumits ...
    Article type: Article
    Session ID: MMS2001-57
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_1
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Co-containing ferrite thin-film media with high coercivity of about 3000 Oe and perpendicular anisotropy were prepared by a reactive ECR sputtering method at a substrate temperature of room temperature to 150 degree Celsius. The thermal stability, recording characteristics and time dependence of reproduced voltage for the Co-containing ferrite thin-film media were investigated. The media were proven to possess a good thermal stability, which was almost same as for a commercial MP tape, and high D_<50> values and a small time decay of reproduced voltage, which were almost same as those of a commercial 20 Gb/in^2 longitudinal hard disk.
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  • Perpendicular magnetic anisotropy and thermal agitation of magnetization in Co(B)/Pd superlattice perpendicular recording media
    T. Shimatsu, M. Terakawa, I. Watanabe, H. Muraoka, Y. Nakamura
    Article type: Article
    Session ID: MMS2001-58
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_9
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Magnetic properties and recoding performance were discussed for [Co/Pd(lnm)]_9 and [(Co-20vol%B)/Pd(lnm)]_9 superlattice perpendicular recording media, as a function of Co or CoB layer thickness, δ_<Co> or δ_<CoB>. Perpendicular magnetic anisotropy K_u of these media shows the maximum values of 5.7x10^6erg/cm^3(Co/Pd) and 3.2x10^6erg/cm^3 (CoB/Pd) at around the thickness of 0.2〜0.3 nm. The K_uV/kT of the Co/Pd media show large values more than 200 (δ_<Co>>0.3nm), while the K_uV/kT in both media significantly decreases as the thickness decreases, which is not coincident with the thickness dependence of K_u. The value of K_u/2πM^2_S in both media increases monotonically as the thickness decreases, and was 〜10 at around the thickness of 0.2〜0.3 nm. TEM images and magnetic characterization revealed that the intergranular exchange coupling of the CoB/Pd media is weaker than that of the Co/Pd media. The signal to medium noise ratio S/N_m of the CoB/Pd media is higher than that of the Co/Pd media, and the S/N_m of the CoB/Pd media increases as the thickness decreases. It is likely that these differences in S/N_m are due to the differences in the strength of intergranular exchange coupling.
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  • Thermal stability and recording characteristics of TbCo/CoCrPt hybrid media for perpendicular recording
    H. Nakagawa, H. Nemoto, Y. Honda, Y. Hosoe
    Article type: Article
    Session ID: MMS2001-59
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_15
    CONFERENCE PROCEEDINGS FREE ACCESS
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    We studied thermal stability and recording characterisics of a hybrid medium consisting of a CoCrPt layer and an exchange-coupled TbCo layer. Adding a thin TbCo layer to a CoCrPt medium increased the squareness and decreased the nucleation field, resulting in the high thermal stability. At low densities, the normalized media noise was reduced by the addition of the TbCo layer. However, at high densities it turned to increase by increasing the TbCo thickness above about 3 nm. On the other hand, the signal output and the resolution were increased by the addition of the TbCo layer. As a result, the SNR was improved by adding a thin TbCo layer.
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  • Measurement of ΔM and magnetization time decay for magnetic fine particles in different sample forms
    Terumitsu TANAKA, Toshiyuki SUZUKI
    Article type: Article
    Session ID: MMS2001-60
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_21
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Measuring ΔM and magnetization time decay for Ba ferrite fine particle assemblies prepared in different sample forms, the effect of inter-particle interaction on magnetization thermal stability was evaluated in the presence of various reverse fields. The inter-particle interaction observed in ΔM plots increases as particles are oriented. It was clarified that positive interaction makes magnetization thermally stable in the presence of weak reverse fields, conversely, it makes magnetization unstable in the presence of strong reverse fields.
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  • Prospects and Subjects for High Recording Density
    Katsumichi TAGAMI
    Article type: Article
    Session ID: MMS2001-61
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_27
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This report describes the NEC's research and development for ultra-high recording density. In these research and developments, subjects for perpendicular magnetic recording have been investigated. Read/write characteristics of Subterabit/in^2 high-density recording using TMR (Tunneling magnetic resistance) head are estimated. Subjects for contact recording techniques and STM (Scanning tunneling microscopy) memory also are described.
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  • Ba Ferrite Particulate Media : History of Development and Future
    Toshiyuki SUZUKI
    Article type: Article
    Session ID: MMS2001-62
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_35
    CONFERENCE PROCEEDINGS FREE ACCESS
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    This paper reviews the developments of Ba ferrite particles and tape/flexible disk applications, which have been developed with expectation for use in perpendicular recording systems with readiness of media mass-production. Ba ferrite particles, produced by a glass crystallization method, features a narrow size distribution and the precise controllability of coercivity by the amount of Co-Ti substitution. 4 MB FDs/FDDs and Hi-8 VCR tapes were commercialized, but unfortunately they could not grasp the market popularity. Recently, finer Ba ferrite particles have been newly developed. They have more excellent recording capability than the old one, but at the same time they have posed thermal stability issue due to the smallness of the particle volume. The mean diameter of around 30 nm was concluded to be the best choice for the new Ba ferrite particles.
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  • [title in Japanese]
    Article type: Appendix
    Pages App1-
    Published: October 11, 2001
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.25.62.0_App1
    CONFERENCE PROCEEDINGS FREE ACCESS
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