日本応用磁気学会誌

磁気記録媒体

SiO₂によるCoPt媒体の低ノイズ化

領内博, 石田達朗, 東間清和, 神前隆

1998 年 22 巻 4_2 号 p. 225-228
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.225

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Research has been done on various ways of reducing noise in the fabrication of thin-film magnetic recording media. Our approach is based on simultaneous sputtering of SiO₂ and Co-Pt on a Cr underlayer at high Ar pressure and at room temperature. The resulting film was composed of fine magnetic grains less than 10 nm in diameter, isolated from each other by SiO₂-rich regions. These fine magnetic grains formed clusters with a diameter of about 30 nm, which grew on top of single Cr columnar grains and were spatially separated from other clusters. The angular dependence of the coercivity suggested that these clusters were more magnetically isolated from each other, with a more coherent magnetization mode, than films deposited at a lower Ar pressure atmosphere or films not composed of SiO₂. As a result, our film displayed lower noise characteristics.

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Baフェライト磁気ディスクの低温作製と記録再生特性

松下伸広, 馮潔, 塩澤友祥, 渡部康, 一瀬誠, 中川茂樹, 直江正彦

1998 年 22 巻 4_2 号 p. 229-232
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.229

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Magnetoplumbite-type Ba ferrite (BaM) layers were deposited on ZnO (002) and Pt (111) underlayers by using a facing-targets sputtering apparatus in a gas mixture of Ar, Xe, and O₂ at various substrate temperatures T_s. A Ba ferrite layer as-deposited on a ZnO underlayer at T_s values above 475°C and one as-deposited on a Pt (mmm) under-layer at T_s values above 500°C revealed clear c-axis oientation. The saturation magnetization 4πM_s was 5.1 kG and 4.0 kG for ZnO and Pt underlayers, respectively. Both underlayers exhibited high perpendicular coercivity H_c⊥ and low in-plane coercivity H_c// of about 2.4 and 0.2 kOe, respectively. A Ba ferrite layer deposited at a relatively low T_s of 300°C and annealed at 800°C in air also revealed excellent c-axis orientation and exhibited a relatively low perpendicular coercivity H_c⊥ of 0.6 kOe. A clear di-pulse was observed for the isolated wave form of a BaM/Pt film as-deposited at T_s of 600°C owing to the perfect perpendicular magnetization orientation, and a relatively high linear recording density D₅₀ of 123 kFRPI was achieved.

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Co-Cr垂直磁化膜の表面H_cと体積H_cに対する第三元素添加効果

渡辺さおり, 有明順, 本多直樹, 大内一弘

1998 年 22 巻 4_2 号 p. 233-236
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.233

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The effects of third additive elements on the surface and volume perpendicular magnetic coercivity of Co-Cr alloy films were studied. The difference of surface and volume coercivities between the coercivity thickness dependences in Co-Cr-Ta and Nb films is discussed. It is clearly shown that the Co-Cr-Nb film shows almost the same tendency in the thickness dependence of both surface and volume coercivity. It is concluded that Co-Cr-Nb films are superior to Co-Cr-Ta in term of magnetic coupling in the film thickness direction, exhibiting a high crystallinity and a high crystal orientation.

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二層膜媒体を用いた垂直磁気記録における媒体厚みの影響

佐々木保, 村岡裕明, 中村慶久

1998 年 22 巻 4_2 号 p. 237-240
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.237

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The effect of the medium thickness in perpendicular magnetic recording on double-layered media is discussed. It was found that the thickness of the medium significantly affected the recording capability of the medium. By improving the coercivity of medium, we obtained high flux density on the surface of a comparatively thick medium.

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薄い裏打ち層を有する垂直媒体のMRヘッドでの記録再生特性

松下慶友, 服部一博, 青山勉, 佐藤勇武

1998 年 22 巻 4_2 号 p. 241-244
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.241

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The recording characteristics of single- and double-layer perpendicular media without and with a thin soft magnetic backlayer were investigated by using merged MR heads. In single-layer media, even a thin soft back-layer with a thickness of 10 nm increased the low-density output and the overwrite property by nearly 4 dB at magnetic spacings of less than 47 nm. In double-layer media with a 10-nm-thick backlayer, no degradation of the recording density was observed.

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磁気ヘッド

NiO/CoO, FeMn,およびNiMn反強磁性材料を用いたスピンバルブヘッドのピン層磁化安定性

石原邦彦, 鈴木哲広, 松寺久雄

1998 年 22 巻 4_2 号 p. 245-248
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.245

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An abnormal reproduced waveform was observed in spin-valve (SV) heads. We show that this abnormal wave-form was caused by instability of the pinned-layer magnetization even below the blocking temperature (T_b). In SV heads with an NiO/CoO-bilayer (NiO/CoO-SV heads), the pinned-layer magnetization is easily aligned to the track width direction and becomes unstable even at room temperature. FeMn-SV heads showed a relatively stable wave-form, in contrast to NiO/CoO-SV heads. However, below a temperature of 100°C, the pinned-layer magnetization reverses and is pinned easily to the direction of the applied current field. On the other hand, the pinned-layer magnetization in NiMn-SV heads is highly stable, mainly because of the high T_b.

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PdPtMn反強磁性材料を用いたデュアルスピンバルブ

岸均, 清水豊, 長坂恵一, 田中厚志, 押木満雅

1998 年 22 巻 4_2 号 p. 249-252
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.249

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The dual spin-valve (DSV) has an MR ratio 1.5 to 2 times more than that of a conventional spin-valve. We investigated the MR properties of a DSV with PdPtMn antiferromagnetic layers, which showed high corrosion resistance and high thermal stability. The magnetization of the free layer is rotated from the easy axis by the magneto-static fields of the two pinned layers. We examined the dependence of the bias field (H_b) on the DSV structure, reducing the pinned layer thickness to decrease the magneto-static field, reducing the Cu spacer thickness to increase the interlayer coupling, and varying the magnetic field generated from the sense current. We succeeded in decreasing the bias field to half that of a symmetric DSV by introducing a thin pinned layer, a thin Cu spacer and an asymmetric DSV.

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MRヘッドの再生特性に及ぼす永久磁石膜形状の影響

石川千明, 戸塚香, 五十嵐万壽和, 鈴木良夫, 仲谷栄伸, 林信夫

1998 年 22 巻 4_2 号 p. 253-256
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.253

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The output fluctuations of magnetoresistive (MR) heads with abutted permanent magnets were analyzed by micro-magnetic simulation. The longitudinal bias field was calculated from the magnetization configuration of the permanent magnet (PM) film. The output fluctuation of the MR head was simulated by using the longitudinal bias field, which was calculated with various interface structures between the MR and PM films. When the PM film covered the track edge of the MR capping layer, the longitudinal bias field near the track edge was locally reduced. The local reduction of the bias field was caused by an extra field generated by a charge appearing at the edge of the region where the PM film overlaps the capping layer. It is proved that an MR head with a PM film covering the edge of the capping layer shows output fluctuation, whereas the output is stable when the PM film does not cover the capping layer.

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MRヘッドギャップ用アルミナ膜の検討

斎藤美紀子, 鈴木富士夫, 横田均, 広瀬安志, 石綿延行

1998 年 22 巻 4_2 号 p. 257-260
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.257

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The insulating properties, internal stress, and film structure of Si-O-added Al-O films, and their etching characteristics when immersed in water, were investigated to determine their suitability as shield MR head materials for high-density magnetic recording. The films showed good insulating properties, low internal compressive stress, and excellent corrosion resistance in water. It is concluded that the Si-O-added Al-O films with thicknesses of up to 50 nm should be adopted to reduce the thickness of gap-insulating film.

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Preparation and Read/Write Performance of Contact SCC-MIG Heads

A. Sato, S. Tsuboi, K. Suemitsu, Y. Tsukamoto, M. Takami, M. Iwakura, ...

1998 年 22 巻 4_2 号 p. 261-264
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.261

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A contact SCC-MIG head with three contact pads was prepare by using the dry etching process, and its read/write performance was evaluated. The magnetic spacing of the contact system was estimated to be about 30 nm and the bouncing height was 10 nm. A D₅₀ of 250 kFCI was achieved by using a gap length of 0.10 μm and a track width of 1.2 μm. The read/write performance can be theoretically improved by reducing the overcoat thickness and/or optimizing the magnetic properties of the medium. Regarding the gap length dependence, the read/write performance was significantly improved by using a small gap length in applications involving narrow magnetic spacing, such as contact recording.

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高周波対応Fe系−新ダブル積層ヘッド

夏井昭長, 武田裕美, 坂口昌也, 石田達朗, 長谷川博幸, 村岡俊作, 高橋健

1998 年 22 巻 4_2 号 p. 265-268
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.265

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In a previously developed double-laminated Fe-based alloy film head, it is thought that local permeability deterioration around the magnetic gap causes disagreement between the actual output and the value estimated from the permeability observed in the solid film. Accordingly, a new double-laminated Fe-based alloy film was developed, making full use of the techniques of double lamination, anisotropy modulation control, and magnetostatic coupling. No severe deterioration of the film‘s permeability caused by its shape factor was observed. The bulk head using this film exhibited higher reproduction output in a wider frequency range without any frequency ripples, resulting in a 7 dB output improvement at 28 MHz over a conventional laminated head using Co-based amorphous alloy film.

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狭トラックMRヘッドを用いた長手媒体の三次元磁化解析

服部一博, 青山勉, 佐藤勇武, 清水幸也, 中村慶久

1998 年 22 巻 4_2 号 p. 269-272
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.269

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The write field distributions of merged MR heads and the magnetization of longitudinal magnetic recording media were investigated by using a three-dimensional simulator. The recording performance of a leading-pole trimmed merged MR head (head-2) is compared with that of a conventional merged MR head (head-1). The write field of head-2 decreases more sharply at the track edge than that of head-1. The magnetization pattern recorded by using head-1 shows track edge hooks; however, fewer hooks were recorded by using head-2. It is confirmed that the effective track width (ETW) recorded by head-2 at a low linear density is narrower and the linear density dependence of the ETW is smaller than in head-1. The phase shift of the output wave recorded by head-2 in the off-track position is smaller than that of head-1. The D₅₀ of head-2 is higher than that of head-1.

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薄膜導体励磁型単磁極浮上ヘッドの試作とその記録特性

佐藤一樹, 村岡裕明, 中村慶久, 片倉亨, 佐藤仁, 矢沢健児

1998 年 22 巻 4_2 号 p. 273-276
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.273

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We fabricated a novel single-pole head on a flying slider for perpendicular magnetic recording. By using three film-conductors to energize a main pole at its end, a high recording sensitivity of 0.03 AT_P-P and a very low inductance around 10 nH were obtained. A D₅₀ value of 135 kFRPI was confirmed, almost the same at that of a bulk coil songle-pole head in sliding contact recording. This head provides an idea of a practical single-pole head for a double-layered perpendicular medium for high-frequency applications.

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垂直二層膜媒体における再生減磁に対する単磁極ヘッドの影響

姜文紅, 村岡裕明, 杉田愃, 中村慶久

1998 年 22 巻 4_2 号 p. 277-280
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.277

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In measurements of time decay in perpendicular double-layered media, a large output decay was observed when a regular single-pole head was used for both writing and reading. Investigation of this phenomenon revealed that the demagnetization of the media was caused by the instability of the domain wall of the main pole film and stray field concentration by the main pole during the reading process. Several countermeasures were proposed.

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記録再生特性

斜め配向薄膜テープの遷移性ノイズと高密度記録再生特性

石田達朗, 東間清和, 杉田龍二

1998 年 22 巻 4_2 号 p. 281-284
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.281

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The noise characteristics of obliquely oriented Co-O thin-film tapes are investigated in relation to the magnetic properties of the tapes. The contribution of the transition noise, which is caused by the irregularity of the magnetic transition region, increases with the squareness ratio of the tape, owing to the large magnetization components in the longitudinal direction. With more perpendicularly oriented tapes, the transition noise is almost negligible, while larger film thickness is necessary to compensate for the output reduction at very low linear densities, resulting in increased non-transition noise. In larger-squareness tapes, the transition noise reduces the C/N ratio in the wavelength region of around 1 μm, although in the shorter-wavelength region, the tapes exhibit a higher C/N ratio than more perpendicularly oriented tapes, owing to the higher output.

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PRML方式における非線形要因のビットエラーレートへの影響

霜越正義, 石田和人, 鈴木幹夫, 高野公史, 兒児直樹, 釘屋文雄

1998 年 22 巻 4_2 号 p. 285-288
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.285

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In MR heads, read-nonlinearity and write-nonlinearity, which is manifested in phenomena such as nonlinear transition shift (NLTS), degrade the bit error rate (BER) performance in a PRML read channel. We discuss a simple method of estimating these nonlinearity effects for a PRML read channel, and compare the calculated and experimental results. In a PRML read channel, the BER can be easily calculated from the noise deviation after the equalization, and the nonlinearities increase the noise deviation. The calculation and experimental results show a proportional relationship between the noise deviation due to read nonlinearity and the absolute value of the amplitude asymmetry. The deviation due to NLTS can be calculated by considering the first and second adjacent transition shifts and write precompensation. The total effects of the nonlinearities are easily calculated by adding the squares of all the noise deviations.

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トラックサーボ特性を考慮したMRヘッドのエラーレートの数値解析

菊地慶子, 三俣千春, 下江治

1998 年 22 巻 4_2 号 p. 289-292
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.289

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The error rate performance of MR heads with tracking servo was investigated. The bathtub curves and the position error signal (PES) were computed by using the cross-track profile estimated by micromagnetic calculation. As the read-track width becomes smaller, the linearity of the PES becomes worse and the off-track tolerance from bathtub curves increases. Consequently, the error rate performance with tracking servo increases. As the track pitch becomes smaller, both the linearity of the PES and the error rate improve.

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薄膜導体励磁型単磁極浮上ヘッドのオフトラックオーバーライト特性

山田洋, 村岡裕明, 杉田愃, 中村慶久

1998 年 22 巻 4_2 号 p. 293-296
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.293

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A submicron track width of 0.4μm was observed by measuring an MFM image with a combination of a single-pole head and a perpendicular double-layered medium. Because of its sharp head field distribution, this combination is considered capable of obtaining a very narrow track-pitch. By measuring the off-track overwrite profiles with a thin-film single-pole flying head, we found that the erase band width was around 25 nm, which was acceptable for merged MR head and perpendicular double-layered medium.

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マイクロ波・磁気光学・光磁気記録

BaFe_12-x(Ti_0.5M_0.5)_xO₁₉ (M = Co, Ni, Zn, Mn, Cu)の電磁波吸収特性

岡山克巳, 太田博康, 吉田好行, 籠谷登志夫, 中村元, 杉本諭, 本間基文

1998 年 22 巻 4_2 号 p. 297-300
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.297

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This paper describes the magnetic and electromagnetic wave absorption properties, from 1 to 20 GHz, of M-type hexagonal ferrites, in which Fe³⁺ is replaced by (Ti_0.5M_0.5)³⁺ (M = Co, Ni, Zn, Mn, Cu). Samples were prepared by a conventional powder metallurgy method. These ferrites exhibited good microwave absorption properties in the X-band range (8-12 GHz), and the maximum reflection loss was calculated to be between - 20 and - 50 dB. In the case of M = Mn, high μ'' values were obtained, which allowed the matching thickness to be reduced to 0.58 mm. It is possible that these M-type ferrites may find applications as microwave absorbers in the X-band range.

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レーザアブレーション法によるガーネット3層膜の作製とその磁気光学特性

石井紀彦, 玉城孝彦, 田中功, 佐藤龍二

1998 年 22 巻 4_2 号 p. 301-304
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.301

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Tri-layered films composed of magnetic garnet Bi, Ge, Co:DyIG, highly Ga-substituted Bi:DyIG, and Bi, Ga:DyIG layers were deposited by the pulsed laser ablation (PLA) method, and their magneto-optical properties were investigated. The first and third magnetic layers in the tri-layered film showed the different Faraday rotation spectrum in the short-wavelength region from 400 nm to 700 nm. The Faraday rotation of the Bi, Ge, Co:DyIG and Bi, Ga:DyIG films had maximum values for wavelength of around 435 nm and 490 nm, respectively. The coercivity (H_c) and Faraday rotation of the Bi_0.31Dy_3.0Ge_0.32Co_0.36Fe_4.01O₁₂ film showed nonlinear dependence on the annealing temperature (T_a), and H_c reached a value of 7 kOe at T_a = 860°C. The same film annealed at T_a=880°C showed a compensation temperature near room temperature.

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Fe (001)膜における極磁気および縦磁気Kerrスペクトル

頼健夫, 片山利一, 湯浅新治, M. Nyvlt, 鈴木義茂

1998 年 22 巻 4_2 号 p. 305-308
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.305

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Magneto-optical polar and longitudunal Kerr effects in bcc-Fe (001) epitaxial films sandwiched between Au (001) layers were studied for Fe thicknesses d_Fe = 3-1000Å in the photon energy range of 1.55-6.2 eV. The polar Kerr rotation peaks related to quantum well states (QWS) fomed in Fe layer disappeared above d_Fe=20Å. In films with d_Fe≥100Å, the polar Kerr spectra above 3.5 eV were substantially the same as the spectrum of bulk Fe. Below 3 eV, on the other hand, a Kerr rotation peak enhanced by the plasma edge of Au at 2.5 eV shifted to the lower energy side with the increase of d_Fe even above 100Å, and the intensity of the pear exceeded the bulk value around d_Fe = 100Å. In the longitudinal Kerr rotation spectra the peaks related to QWS appeared nowhere in the whole range of d_Fe. This suggests that the contribution of QWS to the off-diagonal complex dielectric tensor element responsible for longitudinal Kerr effect is in our Fe films negligible.

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MnSbPt薄膜の微細構造と磁気光学効果

荘司弘樹, 渡辺誠, 斉藤伸, 高橋研

1998 年 22 巻 4_2 号 p. 309-312
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.309

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The magneto-optical (MO) Kerr effect for MnSbPt films with a giant magnetic Kerr rotation was investigated in connection with the microstructure. The results revealed that (1) the PtMnSb phase with fcc structure coherently precipitated at the grain-boundary of the matrix MnSb phase with hcp structure after annealing in the range from 200°C to 300°C, (2) both the MnSb phase and the PtMnSb phase were recrystallized after annealing in the range from 300°C to 400°C, (3) the PtSb₂ phases nucleated and grew to be dendrite as a result of the diffusion of Pt atoms from the PtMnSb phase after annealing at over 400°C, and (4) the change in the MO Kerr effect for MnSbPt films annealed at over 300°C corresponded to the decrease in the volume-ratio of the PtMnSb phase to the MnSb phase, owing to the formation and growth of the PtSb₂ phase.

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MnSbPt薄膜の誘電率テンソルと磁気光学効果

斉藤伸, 渡辺誠, 荘司弘樹, 高橋研

1998 年 22 巻 4_2 号 p. 313-316
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.313

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The mechanism of the enhancement of the MO Kerr rotation for Mn₅₀Sb₄₄Pt₆ film was investigated from the view-points of the phases and their components of the dielectric tensor. As a result, it was found that after annealing at 300°C, (1) for (MnSb)_50-0.5xPt_x (x < 14 at%) films, the PtMnSb phase made a larger contribution to the ε'_xx spectrum than would be expected from the Pt concentration, (2) concerning the ε'_xy at 2.3 eV and 4.7 eV, where the PtMnSb phase showed ε'_xy structure, with increasing Pt concentration x along the line of (MnSb)_50-0.5xPt_x, the value of ε'_xy at 4.7 eV decreased monotonously, but the value of ε'_xy at 2.3 eV was maximum at x=17at%, and (3) for the Mn₅₀Sb₄₄Pt₆ film, the maximum of θ_K, where ε'_xx was relatively small, was originated from ε'_xy.

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MnPt₃/CoPt₃人工格子膜の磁気および磁気光学特性

深江文博, 加藤剛志, 岩田聡, 綱島滋

1998 年 22 巻 4_2 号 p. 317-320
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.317

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The structure and magneto-optical properties of MnPt₃/CoPt₃ superlattices grown at R. T., 300°C, and 500°C were investigated. The formation of a layered structure in the superlattices was confirmed by X-ray measurements. The structure of the sample grown at room temperature was disordered fcc. The Kerr spectrum of this sample was similar to that of a Co₂₅Pt₇₅ disordered alloy. The structure of the sample grown at 300°C was a mixture of the Cu₃Au and CuAu types. The Kerr spectrum showed peaks at 1.3 eV and 4.0 eV, which correspond to the peaks for the MnPt₃ ordered phase and the Co₂₅Pt₇₅ disordered alloy, respectively. The structure of the sample grown at 500°C was of the Cu₃Au type. The Kerr spectrum is similar to that of an MnPt₃ ordered alloy.

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遺伝的アルゴリズムによる積層構造の乱れた磁気光学多層膜の設計

井上光輝, 荒井賢一, 藤井壽崇, 阿部正紀

1998 年 22 巻 4_2 号 p. 321-324
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.321

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A novel technique for designing magneto-optical films is presented: the algorithm, which automatically determines the multilayer structures of films with designated optical and magneto-optical properties, is regarded as an extension of the genetic algorithm. The film properties are designated by a simple fitness function f (x), and the film structure that maximizes f (x) is chosen as the optimum one. The present technique has been used to determine two kinds of film structure: one exhibits the largest Faraday rotation θ_F and the other exhibits high transmissivity T and large θ_F simultaneously. These films were obtained after the evolution of about 2000 generations: in one, T=29% but θ_F = -28 deg/μm at λ = 1.15μm, while in the other, T = 70% and θ_F = -16 deg/μm at the same wavelength of light.

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Ni/PVC, Fe/SiO₂, Co/SiO₂グラニュラー膜の磁気光学効果の増大

情野進, 佐藤勲, 松宮寛昭, 白崎文雄, 北本仁孝, 阿部正紀

1998 年 22 巻 4_2 号 p. 325-328
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.325

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We measured the Faraday rotation (FR) spectra (λ = 500-800 nm) in granular films of Ni/PVC (prepared by spin-coating polyvinyl chloride containing Ni fine powders of ∼20 nm diameter) and (Fe or Co)/SiO₂ (prepared by RF-diode co-sputtering and annealed at 400-900°C). The FR spectrum in the Ni/PVC films was best-fitted by assuming that the volume fraction f of Ni is 0.27, though analysis resulted in f = 0.11, suggesting that the FR is enhanced; a possible explanation is “weak localization of light“ in the granular structure. The FR in the Fe/SiO₂ and Co/SiO₂ granular films increased as the annealing temperature (T_a) was raised, reaching a maximum followed by a decrease. The maximum FR was, however, much smaller than that calculated for the films, probably because the size of the metal particles became comparable with the wavelength of light.

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磁気光学効果のエンハンスメント

桂川忠雄

1998 年 22 巻 4_2 号 p. 329-332
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.329

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Large magneto-optical properties are highly desirable in isolators and such devices. Recently, magneto-optical Faraday effects have been greatly enhanced by localization of light and use of the nonlinear magneto-optical Kerr effect. This paper describes cases of the enhancement of magneto-optical effects: (1) the case in which ultra-fine magnetic particles are used; (2) the case in which localization of light is used, and (3) the case in which a grating is used with a magnetic thin film. The enhancement of the magneto-optical effects in these three cases is over 50 times that in other cases. The total rotation angle 34 degrees at 10 kG with a 100-nm magnetic thin film.

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Cd_1-xMn_xTe薄膜光導波路の光学損失

渡邊一弘, バジムザエツ, 大越正敏, 安藤功兒

1998 年 22 巻 4_2 号 p. 333-336
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.333

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The optical properties of Cd_1-xMn_xTe magneto-optical waveguides grown on GaAs substrates were studied. The insertion of buffer layers of 2-nm-thick ZnTe and 1 -μm- thick CdTe between the substrate and Cd_1-xMn_xTe layers improved the crystalline quality of the waveguides, and reduced the optical loss. Use of a smoothing Cd_1-zMn_zTe layer between the Cd_1-xMn_xTe core layer and Cd_1-yMn_yTe clad layer was also effective in reducing the optical loss. Optical losses of 11 dB/cm, 26 dB/cm, and 88 dB/cm were obtained for wavelengths of 1150 nm, 784 nm, and 633 nm, respectively, for Cd_0.55Mn_0.45Te waveguides.

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矢羽根形状記録磁区の磁区拡大再生

粟野博之, 白井寛, 太田憲雄, 山口淳, 鷲見聡, 虎沢研示

1998 年 22 巻 4_2 号 p. 337-339
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.337

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Magnetic domain expansion readout is studied without the presence of an alternative magnetic field. The reproduced waveform of a crescent-shaped domain 0.08 μm in length reaches 70% of the saturated signal level. However, a circular domain of 0.3 μm diameter does not expand so much. In the case of crescent domain expansion, it is considered that the copied domain shape is different from the original crescent shape in the recording layer, and that this reduces the magnetic energy. The assumption that the copied domain shape of the expansion layer becomes circular agrees well with the experimental result for the domain expansion ratio.

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低再生磁界D-RAD

古田正寛, 太田輝之

1998 年 22 巻 4_2 号 p. 341-344
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.341

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Recently many types of magnetically induced super-resolution (MSR) have been proposed for high-density recording on magneto-optical (MO) disks. Among them, double-mask rear-aperture detection (D-RAD) is the most promising, because of its high resolution and its crosstalk advantage. However, D-RAD requires a high external magnetic field for MSR readout. We investigated MSR by D-RAD in order to reduce the readout magnetic field. By optimizing the structure of MSR by D-RAD, we achieved a small magnetic field of −100 Oe for readout. In recording on a D-RAD MO disk with land/groove recording, a C/N of more than 45 dB for a mark length of 0.27 μm and a cross-talk level of less than −40 dB at a track pitch of 0.7 μm were achieved. In addition, a combination of light intensity modulation direct overwrite (LIMDOW) with D-RAD was achieved by adding on MSR switching layer to D-RAD.

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ハード材料

窒素侵入型化合物Nd₂Fe₁₇N₃単結晶の磁気異方性

小山佳一, 藤井博信, 光藤誠太郎, 本河光博, 香嶋純, 安藤由和, P. C. Canfield

1998 年 22 巻 4_2 号 p. 345-348
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.345

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Single crystals of an interstitially modified nitrogen compound, Nd₂Fe₁₇N₃, were successfully synthesized for the first time by means of the high-pressure N₂ gas nitrogenation technique. High-field magnetization curves along the rhombohedral principal axes for the Nd₂Fe₁₇ and Nd₂Fe₁₇N₃ single crystals at 4.2 K indicated strong anisotropic behaviors, which were analyzed on the basis of a single-ion Hamiltonian including the Zeeman energy, exchange energy, and crystalline electric field (CEF) effect. The results indicate that the second-order CEF coefficient A₂⁰ reaches up to −1.5 × 10³ K/a₂⁰ at 4.2K upon nitrogenation, which is about three times as large as that for Nd₂Fe₁₇.

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Sm₂Fe₁₅CoMn_0.9M_0.1N_x (M = Al, Ti, Ga, Zr, Sn, x≧3)粉末の作製と磁気特性

田島伸, 服部毅, 加藤義雄

1998 年 22 巻 4_2 号 p. 349-352
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.349

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The effects of additives (M = Al, Ti, Ga, Zr, Sn) on the magnetic properties of Sm₂Fe₁₅CoMn_0.9M_0.1N_x coarse particles were systematically examined, including the nitrogenation conditions and nitrogen content It was found that both the coercivity and residual magnetization of Sm−Fe−N particles were enhanced by enrichment of the nitrogen content in combination with addition of Co−Mn−Ti. The magnetic properties of Sm₂Fe₁₅CoMn_0.9Ti_0.1N_5.3 coarse particles ∼50μm in diameter were as follows: σ_s=117emu/g, σ_r=109emu/g, _iH_c=8.6kOe, and (BH)_max= 18MGOe.

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Mn添加Sm₂Fe₁₇N_x系材料の磁気特性と微細構造

今岡伸嘉, 岡本敦, 加藤宏朗, 大砂哲, 平賀賢二, 本河光博

1998 年 22 巻 4_2 号 p. 353-356
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.353

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The magnetic properties and microstructure of Sm₂ (Fe_0.95Mn_0.05)₁₇N_x and Sm₂ (Fe_0.84Co_0.11Mn_0.05)₁₇N_x powders were investigated. It was found by high-field magnetization measurement in steady fields of up to 150 kOe that the intrinsic saturation magnetizations of Sm₂(Fe_0.95Mn_0.05)₁₇N_x and Sm₂ (Fe_0.84Co_0.11Mn_0.05)₁₇N_x x=3.3-5.5 were 130-160 emu/g. The theoretical (BH)_max value for Sm₂ (Fe_0.95Mn_0.05)₁₇N_3.3 is calculated to be about 60 MGOe (ρ=7.70 g/cm³, M_s=15.5kG). The anisotropy fields of Sm₂(Fe_0.95Mn_0.05)₁₇N_x and Sm₂(Fe_0.84Co_0.11Mn_0.05)17N_x powders were estimated to be 140-170 kOe by extrapolation of the magnetization curves. From TEM observations, it was found that the Sm₂(Fe_0.95Mn_0.05)₁₇N_5.5 powder had a cell structure consisting of the crystals about 10 nm in diameter. It is concluded that the magnetic reversal of Sm₂(Fe_0.95Mn_0.05)₁₇N_5.5 powder is pinning-controlled, judging from the microstructure and the relationship between the coercivity and the maximum applied field.

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着磁可能Sm₂Fe₁₇N₃磁石多磁区粒子における着磁および核生成挙動の解析

小林久理真

1998 年 22 巻 4_2 号 p. 357-360
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.357

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Sm₂Fe₁₇N₃ powders used in permanent magnets are composed of three types of particle: (1) single-domain particles (SDPs), (2) multi-domain particles (MDPs) in which the domain walls move under a relation of H_appl. = NM, where N is a demagnetizing factor, M is the magnetization in a particle and H_appl. is an applied magnetic field, and (3) particles that behave as MDPs in a demagnetized state, but can be magnetized to become SDPs under a certain magnetic field and behave as SDPs unless renucleation occurs. The authors studied the magnetization and nucleation behavior of the last type of particles, which they call saturable multi-domain particles (SMDPs). In this report, the relation between magnetization and nucleation fields in SMDPs is measured for isolated and isotropically distributed Sm₂Fe₁₇N₃ particles.

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水素化相分解·脱水素再結合処理により作製した (Nd,Dy)-Fe-Co-B系異方性磁石粉末の磁気特性

中山亮治, 石井義成, 森本耕一郎

1998 年 22 巻 4_2 号 p. 361-364
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.361

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We studied the magnetic properties of Nd-Dy-Fe-Co-B-Zr-Ga magnet powders produced by the hydrogenation-decomposition-desorption-recombination (HDDR) process, using a hydrogen pressure of 0.1 MPa. Magnet powders with _iH_C higher than 1200 kA/m were obtained from alloys of Nd_11.3Dy_1.3Fe_80-yCo_yB_7.0Zr_0.1Ga_0.3, y≤11.6 at%. It was found that annealing in an Ar atmosphere added after the HD treatment in the HDDR process improved the magnetic anisotropy of the magnet powders. Typical magnetic properties of the magnet powders obtained by this process are as follows: B_r=1.27T, _iH_c=1280 kA/m, (BH)_max=283 kJ/m³, and β=-0.44%/°C.

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薄肉成形したNd-Fe-B系焼結磁石の磁気特性

槇田顕, 山下治, 中西昭男

1998 年 22 巻 4_2 号 p. 365-368
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.365

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The granulation of Nd-Fe-B powder was investigated by the spray-drying method, using poly (vinyl alcohol) as a binder to give it good flowability. The amount of oxygen and carbon in sintered magnets can be controlled below the upper limit by cooling the slurry and debinding green compacts in a hydrogen atmosphere. As the granulated Nd-Fe-B powder has good flowability, thin green compacts can be easily produced from it, and the sintered bodies are highly accurate in size. Micro-ring magnets with a thickness of 0.6 mm and thin-plate magnets with a thickness of 0.2 mm were successfully synthesized by spray-dried Nd-Fe-B powder without any serious damage to the surfaces by oxidation, which harms coercivity and the squareness of demagnetization curve.

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Nd₅Fe₇₁Co₅Cu_0.5Nb₁B_17.5交換スプリングボンド磁石の磁気特性

山元洋, 新家徹

1998 年 22 巻 4_2 号 p. 369-372
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.369

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Exchange-spring-bonded magnets of Nd-Fe-Co-Cu-Nb-B system alloys were prepared by using melt-spun ribbons heated at 650°C for 10 min. Bonded magnets of Nd-Fe-Co-Cu-Nb-B system alloys were examined to determine their magnetic properties, low-temperature properties, and irreversible flux losses. The irreversible flux loss of these bonded magnets at 100°C was less than 5%. Spin reorientation was observed below —120°C. The optimum preparation conditions and some properties are as follows: composition, Nd₅Fe₇₁Co₅Cu_0.5Nb₁B_17.5; wheel velocity, 20 m/s; annealing condition, 650°C × 10 min in Ar atmosphere; magnetic properties, J_r=0.776 T, H_cJ = 320.4 kA/m, H_cB = 253.0 kA/m, (BH)_max = 57.82 kJ/m³, H_k/H_cJ × 100 = 20.65%, D=6.17Mg/m³.

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Nd-Fe-Co-V-B系交換スプリング磁石の磁気特性

山元洋, 塩澤真紀

1998 年 22 巻 4_2 号 p. 373-376
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.373

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Exchange-spring magnets of Nd_xFe_86-xCo₈V₁B₅ and Nd_xFe_85-xCo₈V₁B₆ (x=6−9) alloy ribbons were prepared by the single-roller rapid quenching method. The effects of the composition and annealing treatment on the magnetic properties were investigated. The values of (BH)_max and H_cJ were found to increase with the Nd content, while, the value of B_r decreased slightly. The optimum preparation conditions and some properties were as follows: composition, Nd₉Fe₇₆Co₈V₁B₆; roller speed, 20 m/s; annealing condition, 675°C × 0 min; magnetic properties: (BH)_max = 165.4 kJ/m³, H_cJ = 455.4 kA/m, H_cB = 423.3 kA/m, B_r= 1.11 T, α (B_r)= −0.067 (%/°C), β (H_cJ) = −0.33 (%/°C), H_k/H_cJ × 100 = 44.7%, T_c = 448°C. From TEM observation, the particle size of this ribbon was determined to be 20 to 30 nm.

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一軸応力下で結晶化させることにより作製したナノ結晶(Fe, Co)-Nb-(Nd, Pr)-Bバルク磁石の磁気特性

小島章伸, 牧野彰宏, 井上明久

1998 年 22 巻 4_2 号 p. 377-380
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.377

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The magnetic properties of nanocrystalline bulk Fe_100-x-yCo_xNb₂(Nd, Pr)_yB₅ (x=0-20, y=5 and 7) alloys produced by consolidating and crystallizing amorphous powders under uniaxial pressure were investigated. The bulk alloy produced by consolidating amorphous Fe₆₆Co₂₀Nb₂-Pr₇B₅ powder at a temperature (T_s) of 873 K under a uniaxial pressure (P_s) of 636 MPa had a density of 7.56 × 10³ kg/m³ and formed a nanocrystalline composite structure of bcc-(Fe, Co), (Fe, Co)₃B, and Pr₂(Fe, Co)₁₄B phases in the as-consolidated and annealed (973 K) states. Nanocrystalline bulk Fe_100-xCo_xNb₂(Nd, Pr)₇B₅ (x=0-20) alloys showed remanence enhancement, associated with an exchange-spring magnet, and anisotropic magnetic properties presumably due to the alignment of (Nd, Pr)₂(Fe, Co)₁₄B phase caused by crystallization under uniaxial pressure. The maximum energy product ( (BH)_max) measured parallel to the press direction was found to be 94 kJ/m³ for Fe₆₆Co₂₀Nb₂Pr₇B₅.

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Fe-Co-Nd-Zr-B系ガラス合金の結晶化過程と磁気特性

藤田浩一, 張濤, 井上明久, 牧野彰宏

1998 年 22 巻 4_2 号 p. 381-384
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.381

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New Fe-based amorphous alloys exhibiting the glass transition and supercooled liquid region before crystallization were searched for in the composition range of Fe₆₃Co₇Nd_10-xZr_xB₂₀ (x=0 to 6 at%). Amorphous alloys containing 4 to 6 at%Zr were found to exhibit the glass transition followed by a supercooled liquid region. The crystallization of the 4 at%Zr and 6 at%Zr alloys occurred in three stages. In the crystallized state, the alloys exhibited hard magnetic properties, namely, J_s of 1.15 to 1.18 T, J_r of 0.75 to 0.76 T, and Nd₂Fe₁₄B phases for the 4 at%Zr alloy subjected to optimum annealing were about 50 nm and 30 nm, respectively, and the exchange magnetic coupling interaction between the α-Fe and Nd₂Fe₁₄B phases is thought to make possible the appearance of the hard magnetic properties.

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薄板状Fe₃B/Nd₂Fe₁₄B系ナノコンポジット磁石の作製

金清裕和, 広沢哲

1998 年 22 巻 4_2 号 p. 385-388
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.385

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The quenching conditions for the formation of a nanocomposite microstructure in rapidly-solidified Nd₄Fe_77.5B_18.5 alloys were investigated in order to obtain a hard magnetic material consisting of Fe₃B and Nd₂Fe₁₄B in the as-quenched state by means of the Cu single-roll melt-spinning technique. It was found for the first time that as-spun Fe₃B/Nd₂Fe₁₄B hard magnets can be obtained directly from a molten alloy when the melt-spinning process is carried out under a reduced chamber pressure of 1.3 kPa Ar on a Cu-roll surface moving at a velocity of 5 m/s. The as-spun Nd₄Fe_77.5B_18.5 hard magnet has a thickness of 190 μm and magnetic properties of J_r = 1.25 T, (BH)_max = 118.1 kJ/m³, and H_cJ = 276 kA/m at room temperature. The Fe₃B/Nd₂Fe₁₄B nanocomposite hard magnets obtained by this technique may be used to produce thin-plate permanent magnets.

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磁性体物理

小型Mottスピン分析器のSP-SEMへの応用

倉岡義孝, 末岡和久, 岩田達夫, 武笠幸一, 相原龍三, 早川和延

1998 年 22 巻 4_2 号 p. 389-392
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.389

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A spin-polarized scanning electron microscope (SP-SEM) with a retarding-type Mott analyzer was developed. For SP-SEM applications, we improved the figure of merit of the polarimeter, which had been developed in our laboratory, and employed a newly designed secondary electron collector. To avoid the magnetic stray field generated by the magnetic objective lens, a magnetic shield whose shape was designed by means of the finite element method was attached to the lens. Using the SP-SEM system, we observed spin-dependent SEM images of the domain structure of a single Fe crystal (001) surface, and typically observed spin polarization of secondary electrons of about ±14%.

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Cuフェライト膜のJahn-Teller歪みと磁気特性

田中敏彦, 宮本宏之, 佐々木祥敬, 安達和正, 小島進, 千葉雅史, 小泉義晴

1998 年 22 巻 4_2 号 p. 393-396
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.393

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The crystal structure of copper iron oxide (CuFe₂O₄:Cu-ferrite) is transformed from cubic spinel to tetragonal symmetry by the Jahn-Teller (J-T) distortion. The degree of J-T distortion σ is theoretically given by the function σ=σ₀ tanh (|A|σ/R_BT), where σ₀ is the degree of the distortion at 0 K, A is the energy term involved in the distortion, R_B is Boltzmann's constant, and T is the absolute temperature. The films were prepared by vacuum evaporation and solid reaction, and their crystal structure, magnetic coercive force, and initial magnetization energy were investigated. The temperature dependence of the shift of the Bragg angle Δ2θ for XRD, the coercive force H_c, and the initial magnetization energy E_i were well fitted to the function C tanh (α/T−β), where C, α, and β are constants determined by experiment. Consequently, the interaction between the distortion and magnetic properties of Cu-ferrite films was considered to be caused by J-T distortion, and experimental results agreed with the theorem of J-T distortion.

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(Er_1-xTb_x)₂Fe₁₄Bの逐次スピン再配列転移と格子変形

加藤宏朗, 石崎達也, 佐藤文隆, 宮崎照宣

1998 年 22 巻 4_2 号 p. 397-400
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.397

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Highly-oriented (Er_1-xTb_x)₂Fe₁₄B ribbons with 0 ≤ x ≤ 0.45 were fabricated by a rapid-quenching method. The c-axis of the tetragonal cell was aligned perpendicular to the ribbon surface. Magnetostriction measurements were made by using the capacitance method, and showed that the sum of the longitudinal and transverse magnetostriction λ_// + λ_⊥. within the ribbon plane took a maximum at successive spin-reorientation temperatures. A model calculation of the volume change ΔV/V in the vicinity of the spin-reorientation temperatures was made by assuming that only the lowest crystal field term A⁰₂ affects the volume change. This calculation showed that ΔV/V exhibits a sharp peak at spin-reorientation temperatures, which is in accordance with the experimental peaks of λ_// + λ_⊥.

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La_n-nxCa_1+nxMn_nO_3n+1薄膜の磁気的·電気的性質

早川純, 浅野秀文, 松井正顕

1998 年 22 巻 4_2 号 p. 401-404
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.401

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The magnetic and electrical properties of two-dimensional epitaxial a-axis La_n-nxCa_1+nxMn_nO_3n+1 (n=2, 3; x=0.3) films and three-dimensional La_1-xCa_xMnO₃ (x=0.3) film were studied. Various systematic changes in the properties were observed as n (the number of MnO₂ layers) was reduced. These included a decrease in the resistivity peak temperature (T_ρ^max), and enhancement of the magnetoresistance near T_ρ^max and the characteristic low-temperature magnetoresistance whose field dependence has a hysteresis curve. It is concluded that the changes result from a decrease of the transfer (t^c_ij) along the c-axis of the crystal and the effect of spin fluctuation between MnO₂ layers.

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⁵⁷FeメスバウアープローブによるCo/Au人工格子の磁気構造

濱田直, 紬糸信好, 小野輝男, 新庄輝也

1998 年 22 巻 4_2 号 p. 405-408
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.405

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Using a local-doping technique with ⁵⁷Fe MÖssbauer probes, a depth-dependent micromagnetic structure in [Co (20 Å)/Au (20Å)]_N-1/Co (20Å) multilayer films with perpendicular anisotropy was investigated. As a result, (1) a smooth spin reorientation from in-plane to out-of-plane was found as a function of the laminating number N ac-companied by a change in the micromagnetic structure, and (2) the average spin orientation and dipole field in Co layers of [Co/Au]₃₀/Co were found to be strongly depth-dependent, that is, they were closer to the film normal at the middle part of the multilayer than near the surface. The latter findings were attributed to the presence of a flux closure pattern in the perpendicular plane throughout the multilayer structure. The paper also discusses a spin rearrangement phase transition of the magnetic multidomain structure in a [ferromagnetic/nonmagnetic]_N multilayer film with moderate perpendicular anisotropy as a parameter of N.

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新しい希薄磁性半導体Zn_1-xNi_xTeの合成と評価

千葉淳弘, 田上尚男, 秋本良一, 大成誠之助, 安藤功兒

1998 年 22 巻 4_2 号 p. 409-412
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.409

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After establishing the usefulness of the ion implantation technique for synthesizing diluted magnetic semiconductors (DMSs) in the case of Zn_1-xCo_xTe, we have used the technique to obtain Ni-based DMSs, which have not been reported before. Ni ions were implanted into an epitaxially grown ZnTe film. The magnetic circular dichroism (MCD) spectra of the implanted films clearly showed that the Ni ions replaced Zn ions and induced a Zeeman split of the optical transitions. Analyses of the MCD spectra and the Zeeman splitting showed that the p-d exchange interaction in Zn_1-xNi_xTe was antiferromagnetic, and that its magnitude could be the largest ever reported for DMSs.

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薄膜

FeB電析膜の軟磁気特性に及ぼす複合錯化剤の影響

藤田直幸, 井上光輝, 荒井賢一, 藤井壽崇

1998 年 22 巻 4_2 号 p. 413-416
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.413

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To obtain amorphous FeB-plated films with soft magnetization, the effect of a combined complex agent of potassium sodium tartrate (KNaC₄H₄O₆ · 4H₂O) and ammonium sulfate ( (NH₄)₂SO₄) on the film properties was investigated. Soft magnetic films with coercivities of less than 4 Oe were obtained by using a bath composition of KNaC₄H₄O₆ · 4H₂O = 600mmol/L and (NH₄)₂SO₄ = 80mmol/L. These soft films also exhibited large magnetostriction of 26 × 10^-6, suggesting that the use of the combined complex agent is very effective for obtaining FeB amorphous films that have soft magnetic properties and large magnetostriction simultaneously. Change in composition of films along their thicknesses is considered to be responsible for the magnetic softening of FeB-plated films.

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アモルファスFeB薄膜の磁気および磁歪特性に対する希土類元素添加効果

弥生宗男, 松田美也, 藤井壽崇, 井上光輝, 荒井賢一

1998 年 22 巻 4_2 号 p. 417-420
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.417

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Improvements in the magnetic and magnetostrictive properties of amorphous FeB sputtered films were achieved by doping them with rare earth elements (RE = Pr and Tb) were examined in detail for the composition system Fe_100-x-yB_xRE_y (x = 15-40 at%, y = 0-3.5 at%). It was found that magnetic softening is promoted by adding a small amount of RE (y = 1 at% for Pr, y = 1.5 at% for Tb), while ensuring that film maintains a relatively high magnetostriction constant. These properties remain almost completely insensitive to thermal annealing at temperatures up to 350°C, suggesting that RE elements with large ion radii act as impurity elements, causally stabilization of the amorphous structure and an increase in the electrical resistivity. The linear change of λ vs. H without any hysteresis loop and the high magnetostrictive sensitivity dλ/dH are very favorable for sensor and/or actuator applications.

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Fe-N薄膜の生成に及ぼすバイアス効果

鵜飼克宏, 新妻清純, 移川欣男

1998 年 22 巻 4_2 号 p. 421-424
発行日: 1998年
公開日: 2007/06/29

DOIhttps://doi.org/10.3379/jmsjmag.22.421

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Fe-N thin films were prepared on crystallized glass and MgO (100) single-crystal substrate at room temperature by RF sputtering with an RF bias ranging from 0 W to 75 W at a deposition rate of between 0.5Å/s and 0.8Å/s. The X-ray diffraction peaks of γ'-Fe₄N decreased with increasing RF bias. In Fe-N thin films prepared on crystallized glass, an α''-Fe₁₆N₂ phase and α'-martensite phase were not formed, and the saturation magnetization M_s of the films did not exceed that of bulk α-Fe. In the Fe-N thin films prepared on MgO (100) single-crystal substrate with RF biases of 20 W and 25 W, α'-martensite phase were formed. The M_s for an RF bias of 20 W was 227 emu/g, which was 4.1% higher than that of bulk α-Fe.

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