ITE Technical Report
Online ISSN : 2424-1970
Print ISSN : 1342-6893
ISSN-L : 1342-6893
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21.71
Displaying 1-14 of 14 articles from this issue
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  • [title in Japanese]
    Article type: Cover
    Pages Cover1-
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_Cover1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • [title in Japanese]
    Article type: Index
    Pages Toc1-
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_Toc1
    CONFERENCE PROCEEDINGS FREE ACCESS
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  • Perpendicular Magnetic Anisotropy and Layered Structure in Co/Pd Multilayered Thin Films
    Hoon-Sang Oh, Byung-Il Lee, Seung-Ki Joo
    Article type: Article
    Pages 1-7
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_1
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Magnetic properties of Co/Pd multilayers with different interface/micro structures were investigated and the anisotropy dependence on the film structure is reported. It was found that the flat underlayer is required for attaining high perpendicular magnetic anisotropy energy. Ion, bombardment experiment showed that the perpendicular magnetic anisotropy of Co/Pd multilayers is closely related to the film stress as well as the layered structure. Co/Pd films lost multilayered structure by the heat treatment at the temperature above 400℃, but the magnetic easy axis was still maintained along the perpendicular direction after the complete mixing of Co and Pd layers, which was attributed to the notable enhancement of crystalline quality of the film.
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  • Preparation of Perpendicular Anisotropic Co Ferrite Films below 100℃
    Yoshitaka KITAMOTO, Shusuke KANTAKE, Fumio SHIRASAKI, Shin-ichi TAKAYA ...
    Article type: Article
    Pages 9-13
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_9
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Perpendicular anisotropic Co_xFe_<3-x>O_4 films of 25〜200 nm in thickness were successfully obtained by the spin-spray ferrite-plating method at 90℃ for perpendicular magnetic recording media. Perpendicular coercivity H_<c⊥> of the Co_xFe_<3-x>O_4 took the maximum around at 0.5,and the value of H_<c⊥> was over 2000 Oe even at 25 nm in the film thickness. Due to optimizing a concentration of NaNO_2 in an oxidizing solution, in-plane coercivity H_<c//> decreased down to 300 Oe while H_<c⊥> was kept over 2000 Oe. Mossbauer analyses also show the films have excellent perpendicular magnetic anisotropy. The angular dependence of the coercivity shows the reversal of the magnetization takes place with a rotation mode, which is very close to Co-Cr sputter-deposited films.
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  • Structure and magnetic properties of Ni-Zn ferrite thin films prepared by RF magnetron sputtering at room temperature
    Jang-Sik Lee, Byung-Il Lee, Seung-Ki Joo
    Article type: Article
    Pages 15-19
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_15
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Ni-Zn ferrite thin films were prepared by RF magnetron sputtering at room temperature. The structure and magnetic properties of the as deposited films were investigated as a function of oxygen partial pressure, working pressure and RF power. Ni-Zn ferrite thin films with spinel structure could be obtained by adjusting the process parameters without substrate heating or post heat treatment. The Ni-Zn ferrite thin film deposited with the optimized condition showed saturation magnetization of 165 emu/cc and coercivity of 36 Oe.
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  • Switching Mechanism of Perpendicular Magnetic Recording Medium at Very Low Temperature
    Kazuetsu Yoshida, Yoshiyuki Hirayama, Masukazu Igarashi, Masaaki Futam ...
    Article type: Article
    Pages 21-26
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_21
    CONFERENCE PROCEEDINGS FREE ACCESS
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    The decrease in the magnetic domain size is necessary to reduce the noise of a perpendicular magnetic recording medium. To obtain the guiding principle for making the magnetic domain finer it is necessary to understand the switching mechanism of a medium. Conventional switching mechanism models based on the micromagnetics does not take into account thermal fluctuation. We compare the calculated magnetization curves with those measured at 10 K which do not suffer from thermal fluctuation and we find that the magnetization curves can be reproduced by assuming nucleation regions on the surfaces of magnetic thin-films.
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  • Quantitative Determination of Dynamic Parameters in Domain Reversal Behavior
    Sug-Bong CHOE, Sung-Chul SHIN
    Article type: Article
    Pages 27-31
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_27
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A novel method to quantitatively analyze the domain reversal behavior has been adopted to understand we total-thickness-dependent domain reversal behavior in Co/Pd multilayers. The wall-motion speed and the nucleation probability were simultaneously determined by analyzing the serial domain images observed using a real-time domain observation system. Using this method, sensitive decrement of the wall-motion speed with increasing the total multilayer thickness has been found to be responsible for the contrasting reversal behavior in Co/Pd multilayered system.
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  • Particle Size Dependence of Recording Performance and Thermal Stability in High Density Particulate Tapes
    Toshiyuki SUZUKI, Yuji Hayashi, Tomohiro Mitsgi
    Article type: Article
    Pages 33-40
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_33
    CONFERENCE PROCEEDINGS FREE ACCESS
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    Using particulate tapes that were composed of magnetic fine particles, of which physical size and magnetic properties are known, high-density digital recording performances and thermal stability of magnetization were studied experimentally and theoretically. Reproduced signals more than 600 kFRPI were observed for an MP tape, which is composed of 70-nm average length metal particles. When particle length was greater than bit lengths, its size effect was observed in recording performances, but size distribution effect was less significant, if deviation was less than 30% of the mean length. By theoretical analysis of magnetization reversal, based on the Arrhenius equation, particle size and size distribution were found to play very important role in magnetization time decay.
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  • Monte-Carlo simulation for soft-magnetic thin film
    Kenji TAN, Yoshihisa NAKAMURA
    Article type: Article
    Pages 41-46
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_41
    CONFERENCE PROCEEDINGS FREE ACCESS
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    To achieve high speed response of GMR memory it is necessary that magnetic structures are chaged by rotations of magnetizations. So a soft-magnetic layer of each memory unit has to take single domain structure without magnetic domain walls. Stable magnetic structures of various film thicknesses were obtained by using Monte-Carlo method developed by us. Stable magnetic structures of each case in various uniform field were calculated too. And the field which is needed to obtain a single domain was calculated.
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  • Effects of MR heights on MR response of a shielded MR head with abutted permanent magnet films
    K.J. Lee, S. Lee, T.D. Lee
    Article type: Article
    Pages 47-51
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_47
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A micromagnetic calculation of a shielded MR head with abutted permanent magnets has been described. Effects of MR heights on MR response are studied by examining such parameters as signal output, pulse width, peak asymmetry, baseline shift, magnetic center shift and magnetic track width. From this work, it is found that the increase of MR height makes the MR response worse both in the properties of on-track and off-track. This behaviour is similar to the exchange biasing case.
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  • GMR Response for Current in Yoke Type MR Head
    Kiyoshi YAMAKAWA, Kazuhiko SHINTAKU, Kazuhiro OUCHI
    Article type: Article
    Pages 53-58
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_53
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A new yoke type GMR head with a vertical configuration where the sense current flows through the magnetic yoke films into the GMR element was studied. To investigate a potential of this head, a wafer test was carried out. The spin valve GMR sensors with CoZrNb yokes were fabricated on wafers, and GMR responses of the test structure were measured under uniform field excitations. Changes in magnetoresistance for the yoke type sensors was obtained as large as that of yoke-less sensors, though the offsets in the response curves was appeared depending on the overlapped area between the yokes and the GMR elements. It was found that the laminated free layer of the GMR element was useful to the reduction of coercive force of the response, and the shorter yoke-GMR spacing was preferable to obtain a wider signal dynamic range for linear operation.
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  • A New Multilayered Structure for Advanced Magnetoresistive Random Access Memory (MRAM) Applications
    Won-Cheol Jeong, Byung-Il Lee, Seung-Ki Joo
    Article type: Article
    Pages 59-63
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_59
    CONFERENCE PROCEEDINGS FREE ACCESS
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    It is common practice to use two magnetic layers separated by the non-magnetic layer such as copper for the spin valve system. In this work, three magnetic layers (NiFe, NiFe/Co, and Co) were used to form a spin valve and its magnetic properties were characterized. Due to the difference in the coercive field of the three magnetic layers, two plateaus could be obtained in M-H and R-H curves. Each plateau plays as a recording level. According to the external magnetic fields, four distinguishable resistance states could be identified. The optimum preparative condition for the well defined four states turned out to be NiFe (6 nm)/Cu (2 nm)/NiFe (1.5 nm)/Co(4.5 nm)/Cu(2 nm)/Co (3 nm), where the multi-bit MRAM (more than two bits) was proved to be realized.
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  • Read/Write characteristics of perpendicular magnetic hard disk using ferrite substrate
    Tomohiro SHOJI, Isao WATANABE, Hiroaki MURAOKA, Yutaka SUGITA, Yoshihi ...
    Article type: Article
    Pages 65-69
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_65
    CONFERENCE PROCEEDINGS FREE ACCESS
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    A soft-magnetic thin film is generally used for back-layer of double-layered perpendicular magnetic hard disk. However, it is feared that the permeability of back-layer decreases due to eddy current at high frequency recording because electric resistivity of Ni-Fe-Nb is low value. In order to prevent the eddy current, a perpendicular magnetic hard disk using a ferrite substrate that has both soft-magnetic properties and high resistivity was prepared. Experimental result with a single pole head shows that the ferrite substrate disk has higher recording sensitivity than a Ni-Fe-Nb back-layered disk for a wide range of recording density. The fact means that the ferrite substrate with high electric resistivity is useful for high frequency recording.
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  • [title in Japanese]
    Article type: Appendix
    Pages App1-
    Published: November 21, 1997
    Released on J-STAGE: June 23, 2017
    DOIhttps://doi.org/10.11485/itetr.21.71.0_App1
    CONFERENCE PROCEEDINGS FREE ACCESS
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