日本応用磁気学会誌

メディア I

プラズマフリースパッタ Co-Cr 膜における結晶子のナノ構造と極微細 Coリッチ領域

直江正彦, 門倉貞夫

1997 年 21 巻 S_1_PMRS_96 号 p. S1_1-4
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_1

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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.

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Co-Cr薄膜形成における熱流計測によるスピノーダル分解プロセスの評価

門倉貞夫, 直江正彦

1997 年 21 巻 S_1_PMRS_96 号 p. S1_5-9
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_5

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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.

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ポストアニールを用いて形成したCoPt基合金媒体に及ぼすCrの含有効果

向井良一, 山中一典, 押木満雅

1997 年 21 巻 S_1_PMRS_96 号 p. S1_10-14
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_10

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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/H_k^grain of maximum value 0.46 were obtained after post annealing at 460°C.

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Co-Cr薄膜作製における下地層，Ta添加物およびガス圧力の最適化

野田紘憙, 川鍋尚, 直江正彦

1997 年 21 巻 S_1_PMRS_96 号 p. S1_15-18
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_15

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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.

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垂直磁化膜におけるバックリング様式

石井良博, 鈴木伸吾

1997 年 21 巻 S_1_PMRS_96 号 p. S1_19-23
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_19

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The magnetization buckling mode is studied in a perpendicular magnetic film with columnar structure. The calculated nucleation field H_N of the buckling mode is compared with H_N 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 H_N of the buckling mode is very close to H_N 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.

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メディア I I

活性化磁気モーメントを用いた粒子性ノイズの簡略式とCo-CoO系斜め蒸着膜の媒体ノイズ

高山孝信, 久保田隆, 飯村誠, 平野広, 中島八重子

1997 年 21 巻 S_1_PMRS_96 号 p. S1_24-28
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_24

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To understand the noise characteristics in obliquely evaporated Co-CoO films, simplified formula of particulate component of medium noise was deduced. Using activation magnetic moment (A) as a mean magnetic moment of the constituent particles in the film, medium noise power was expressed proportional to the product of A, saturation magnetization and the film thickness. An excellent correlation between measured medium noise and calculated one were obtained, although the noise was slightly high in case of easy axis being inclined in the film plane.

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Co-Cr薄膜の保磁カと磁気異方性の膜厚方向分布と記録再生特性

中川茂樹, 高山誓龍, 直江正彦

1997 年 21 巻 S_1_PMRS_96 号 p. S1_29-33
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_29

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Perpendicular coercivity of the surface layer H_{c ⊥}(s) and that of the initial layer H_{c ⊥}(i) were determined by Kerr loop tracer. The difference between H_{c ⊥}(s) and H_{c ⊥}(i) is correlated to ΔH_c which is considered to express the degree of homogeneity of the H_c distribution in the film. Better c-axis orientation and high Cr content seemed to be essential factor to get good homogeneity of H_c. Good c-axis orientation and relatively high H_{c ⊥}(i) cause better recordeing performance and low medium noise characteristics.

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酸化物磁性薄膜による等方性磁気ディスクの作製と記録再生特性

松下伸広, 野間賢二, 中川茂樹, 直江正彦

1997 年 21 巻 S_1_PMRS_96 号 p. S1_34-37
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_34

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Co-Zn ferrite films were deposited using the facing targets sputtering apparatus and their read/write characteristics were investigated as well as crystallographic and magnetic ones. Co-Zn ferrite films deposited at substrate temperature T_s of 100 and 400 °C revealed very smooth surface and the minimum center-line average roughness R_a were 2.5 and 3.0 nm, respectively. They were composed of crystallites with (111) and (311) orientation and possessed an isotropy and in-plane magnetic anisotropy. High linear recording density of about 114 kFRPI was achieved for specimen disks with (111) orientation which were deposited on fused quartz disk substrate using MIG type head with gap length of 0.27 μm.

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招待セッション I

ビデオ用ハードディスクへの期待

大島英男

1997 年 21 巻 S_1_PMRS_96 号 p. S1_38-43
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_38

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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.

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単磁極ヘッドを用いる垂直磁気記録の現状と課題

中村慶久

1997 年 21 巻 S_1_PMRS_96 号 p. S1_44-53
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_44

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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.

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MRヘッドに対応した垂直磁気記録媒体

池田圭宏, 園部義明, 内田博, 豊岡孝資

1997 年 21 巻 S_1_PMRS_96 号 p. S1_54-59
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_54

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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.

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「長手記録の展望」

－長手記録課題と垂直記録との比較－

田上勝通, 奥村俊之

1997 年 21 巻 S_1_PMRS_96 号 p. S1_60-64
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_60

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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.

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メディア III ＋信号処理

低温熱処理によるBaフェライトスバッタ膜の作製と磁気特性

柿崎浩一, 平塚信之

1997 年 21 巻 S_1_PMRS_96 号 p. S1_65-69
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_65

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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.

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原子層積層法による高密度磁気記録媒体用C軸配向Baフェライト薄膜の作製

清水英彦, 篠崎秀明, 星陽ー, 加藤景三, 金子双男, 井川博行

1997 年 21 巻 S_1_PMRS_96 号 p. S1_70-73
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_70

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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.

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MRヘッドの非線形性の新しい定量化手法

岡崎裕

1997 年 21 巻 S_1_PMRS_96 号 p. S1_74-77
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_74

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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.

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パーシャルイレージャを伴う非線形チャネルのニューラルネットワーク等化

若宮幸平, 大沢寿, 岡本好弘, 斎藤秀俊

1997 年 21 巻 S_1_PMRS_96 号 p. S1_78-82
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_78

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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.

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MRヘッド非線形歪のニューラルネットワーク等化

若宮幸平, 大沢寿, 岡本好弘, 斎藤秀後

1997 年 21 巻 S_1_PMRS_96 号 p. S1_83-86
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_83

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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.

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（1，7）RLL符号に対するISIキャンセラを備えたPRML方式の誤り率特性改善

岡本好弘, 宮下晴旬, 斎藤秀俊, 大沢寿

1997 年 21 巻 S_1_PMRS_96 号 p. S1_87-90
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_87

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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.

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招待セッション I I

垂直磁気記録に於ける課題

押木満雅

1997 年 21 巻 S_1_PMRS_96 号 p. S1_91-97
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_91

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The perpendicular magnetic recording has been investigated for 20 years, whereby the head and the recording media are improved. HDD is made for the inprovement of head and media.
In this inprovement, some unexpected problems such as the instability of magnetic domeins and the contac sliding occur. In this paper I will describe some problems which we encounterd for the practical of the perpendicular magnetic recording.

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単層垂直磁気ディスク媒体の高S/N化

平山義幸, 伊藤研也, 本多幸雄, 二本正昭

1997 年 21 巻 S_1_PMRS_96 号 p. S1_98-103
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_98

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Noise characteristics and magnetization decay of CoCr-alloy single-layered perpendicular magnetic recording media have been investigated. Noise characteristics of CoCr₁₉Pt₁₀ media are improved, by employing CoCr₃₅ underlayer, by reducing cystal grain diameter, and by adding Ta to the magnetic layer. Remanent magnetization decay of CoCrPtTa media are measured. The decay rate can be reduced by employing CoCr₃₅ underlayer. It can be further reduced by making M_r/M_s ratio higher.

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三層垂直媒体の高S/N化および記録信号の安定性

西原敏和, 安藤敏男

1997 年 21 巻 S_1_PMRS_96 号 p. S1_104-108
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_104

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SNR and signal-stability in CoCr Ta/CoZrNb/CoSm triple-layer perpendicular media have been studied. Low medium noise was obtained by (1) uniformity of the magnetic direction in the CoZrNb layer exchange coupled with the CoSm layer (2) optimal saturation magnetization and thickness of the CoCrTa perpendicular layer.
Recorded signals were stable under the conditions of RT·15hours and 60°C·5hs. Stray field didn't cause any decay of signals for the medium with a 600nm-thick CoZrNb layer.

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MRヘッドの高密度化

松崎幹男

1997 年 21 巻 S_1_PMRS_96 号 p. S1_109-112
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_109

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We aim at realizing over 10G bit / in² HDD in the near future. In this paper I will review the MR-inductive combination head technology about high TPI and BPI for realization of the Ultra high areal density recording.

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縦型MRヘッドによる高記録密度化

高田昭夫, 本田忠行, 柴田拓二, 福山宗克, 早田裕

1997 年 21 巻 S_1_PMRS_96 号 p. S1_113-117
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_113

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We have developed the vertical MR/inductive head for high recording density of the hard disk drive. In this head, the read head has the vertical MR sensor. In this paper, we describe the structure and the performance of the vertical MR/inductive head.

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単磁極ヘッドによる垂直磁気記録のMRヘッド再生特性

村岡裕明, 山田洋, 中村慶久, 阿部岩男, 矢沢健児

1997 年 21 巻 S_1_PMRS_96 号 p. S1_118-122
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_118

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Reading characteristics of MR head for perpendicular magnetic recording is investigated with a simulation based on the reciprocity theory and experiments using a single for wring. Double layer perpendicular medium is used. Narrower isolated pulse-width and higher D₅₀ than longitudinal recording even with an MR head of the same shield gap length is confirmed theoretically and experimentally. A D₅₀ of 270 kFRPI and a SN ratio of more than 30 dB_pp/rms up to about 200 kFRPI is obtained with a differentiator.

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単層垂直磁気ディスクをベースにした信号処理方式

梅本益雄

1997 年 21 巻 S_1_PMRS_96 号 p. S1_123-126
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_123

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A high-order partial response (PR) that is generally represented by -(1+D)(1-Dⁿ)² and that will provide both high density and high speed in HDD(hard disk drive) using perpendicular magnetic recording, is proposed. By using a pre-coding 1/(1+D), the n-bit interleaving operation for high speed processing can be used.

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二層垂直ディスク・MRヘッド再生における再生波形の微分等化とC/N，BERの関係

石川清彦, 沼澤潤二, 大島英男

1997 年 21 巻 S_1_PMRS_96 号 p. S1_127-131
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_127

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The C/N and the byte error rate (BER) were investigated, using a double-layered perpendicular magnetic disk with a merged AMR head (R/W track width = 2.3/3.0 μm). The PRML read channel was used to measure the BER. The reproduced signal was differentially equalized and detected by PRML. The bit rate was 57 Mbps (group-coded data rate: 64 Mbps). A BER of under1.0×10^-7 was obtained at 242 kfci, using the differential equalizer with an optimized cut-off frequency of 31.8 MHz to obtain the minimum BER.

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ヘッド・スライダー＋記録再生特性 I

低浮上型単磁極ヘッドの浮上特性と記録再生特性

高山昭夫, 葉新華, 伊藤秀哉, 桜井徹, 本田弘司

1997 年 21 巻 S_1_PMRS_96 号 p. S1_132-135
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_132

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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.

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垂直磁気記録用書き込みヘッドの記録磁界の最適化

清水幸也, 西田周治, 山田洋, 村岡裕明, 中村慶久

1997 年 21 巻 S_1_PMRS_96 号 p. S1_136-139
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_136

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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.

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コンタクト記録方式の潤滑剤設計

柳沢雅広, 佐藤明伸, 安食賢

1997 年 21 巻 S_1_PMRS_96 号 p. S1_140-143
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_140

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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.

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薄膜テープを用いた高密度記録

石田達朗, 杉田龍二, 東間清和, 吉本和也

1997 年 21 巻 S_1_PMRS_96 号 p. S1_144-148
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_144

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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.

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高密度記録用Co-γFe₂O₃媒体の作製および記録特性

土井孝紀, 田万里耕作, 安藤貴之, 山本節夫, 栗巣普揮, 松浦満

1997 年 21 巻 S_1_PMRS_96 号 p. S1_149-153
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_149

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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.

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垂直磁気記録媒体のノイズ特性

安藤貴之, 山本節夫, 栗巣普揮, 松浦満, 土井孝紀, 田万里耕作

1997 年 21 巻 S_1_PMRS_96 号 p. S1_154-158
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_154

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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 S_p-p/N_m,rms than various longitudinal recording media now on the market at high recording densities over 40 kFRPI.

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薄層Baフェライトフレキシブルディスク媒体と狭ギャップMIGヘッドによる高密度記録

本多直樹, 駒木根隆士, 大内一弘

1997 年 21 巻 S_1_PMRS_96 号 p. S1_159-162
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_159

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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. S_pp/N_rms 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.

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リングヘッド－垂直面内複合型媒体系におけるスペーシングの影響

黒川義昭, 尾上貴弘, 宮本宣明, 本間敬之, 逢坂哲彌

1997 年 21 巻 S_1_PMRS_96 号 p. S1_163-168
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_163

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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.

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リングヘッド記録用垂直媒体の記録特性とノイズ特性

梁瀬智, 呉連軍, 本多直樹, 大内一弘

1997 年 21 巻 S_1_PMRS_96 号 p. S1_169-172
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_169

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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.

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記録再生特性 I I

2層垂直磁気記録媒体におけるエッジノイズ検討

是成貴弘, 坪井眞三, 奥村俊之, 松寺久雄, 田上勝通

1997 年 21 巻 S_1_PMRS_96 号 p. S1_173-176
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_173

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Track edge noise for perpendicular magnetic recording medium is analyzed with off-track noise profile for reverse-dc erased track. It is found that bit-edge noise for perpendicular medium is nearly zero. The edge noise arises from transition edge, which noise also causes at side erased band.

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垂直磁気記録トラックエッジのMFMによる評価

本多幸雄, 平山義幸, 伊藤研也, 二本正昭

1997 年 21 巻 S_1_PMRS_96 号 p. S1_177-182
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_177

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Track edge magnetization structures for a single-layered perpendicular media recorded with ring-type head are observed by magnetic force microscopy (MFM). Quantitative analysis of the microscopic magnetization structure is carried out through spectrum analyses of the MFM images. Magnetization structures with sharp track edge profile are formed by using a trimmed symmetrical pole tip shap write head. Several peaks in the Fourier-transformed spectra are considered to reflect the presence of magnetization irregularities. Medium noise measured at the recorded track edge is about 2.6dB larger than that measured from the DC-erased area.

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CoCrPtTa単層垂直磁気ディスク媒体/リングヘッド記録方式による高密度磁気記録の検討

伊藤研也, 二本正昭, 平山義幸, 本多幸雄, 丸山洋治, 井手浩

1997 年 21 巻 S_1_PMRS_96 号 p. S1_183-186
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_183

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High density magnetic recording is investigated for a combination of single layered perpendicular media and ring-type heads. Experimental results show that the linear recording resolution(D50) of 260kFCI is achievable with a CoCrPtTa perpendicular medium in combination with a narrow gap flying write head and an MR head under a magnetic spacing of about 40nm. D₅₀^*=300kFCI is achievable with the medium in combination with a contact read/write head. It is thus shown that the recording linear density can be increased greatly by employing the present recording system.

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垂直記録情報の熱安定性

佐藤賢治, 奥山智明, 岡本巌, 篠原正喜

1997 年 21 巻 S_1_PMRS_96 号 p. S1_187-191
発行日: 1997年
公開日: 2011/12/15

DOIhttps://doi.org/10.3379/jmsjmag.21.S1_187

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Recorded magnetization information of perpendicular and longitudinal Co74-Cr17-Pt5-Ta4 media were observed by magnetic force microscopy (MFM). We found that recording information of the thin longitudinal medium (8.5 nm thick, Br·t=17 G·μm) was fluctuated by the thermal treatment (200°C, 3 hour). Perpendicular recording media can be thicker than longitudinal media to achieve same recording density, so that thermal fluctuation of perpendicular media information is smaller than longitudinal media.

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