著者

錦織 圭史 村上 元良 内田 清 尾留川 正博 宮武 範夫

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.21, no.4, pp.321-324, 1997-04-15

被引用文献数

1

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The potential advantages of magnetically induced super-resolution (MSR) for high-density recording in magneto-optical disks have spurred the study of various related technology. MSR systems can read signals from a smaller area than the laser spot area by using magnetic films with different temperature characteristics. Most MSR systems require an external magnetic field in the readout. We have developed a new type of MSR (S-RAD) that does not require an external magnetic field. The front masking area of the S-RAD is formed by shrinking the recording mark in the readout layer. This paper describes the readout principle and readout characteristics of S-RAD. A C/N of 49 dB was obtained at the 0.5μm recording mark. A crosstalk level of less than -40 dB was obtained at a track pitch of 0.8 μm.We believe that S-RAD has sufficient potential to allow practical use of high-density magneto-optical recording.

著者

井浦 聡則 久保田 均 安藤 康夫 宮 照宣

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.26, no.6, pp.839-842, 2002-06-01

被引用文献数

3

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The annealing temperature dependence of the tunnel magnetoresistance (TMR) ratio for ferromagnetic tunnel junctions prepared by various oxidation methods was measured. A junction prepared by plasma oxidation showed a TMR ratio of 31.4% before heat treatment, and this ratio increased to 49% after annealing at 300℃ On the other hand, the TMR ratio for a junction prepared by radical oxidation showed a maximum at 350℃. The enhancement of the thermal stability resulted from the different oxidation progress depending on the oxidation method.

著者

村田 勝昭 原田 耕介 八木 正昭 遠藤 功 木田 隆夫

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.23, no.4, pp.1505-1508, 1999-04-15

被引用文献数

3

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We present the magnetic characteristics of a compressed amorphous powder core developed in our laboratory and a boost converter using this core. The powder core has a higher saturated flux density and lower power dissipation than a conventional ferrite core. A boost converter using this powder core is highy efficient and very small.

著者

手塚 耕一 河崎 悟朗 神頭 信之 下川 聡 中尾 古宏 内山 隆

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.28, no.12, 2004-12-01

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現行MOやDVDの約13倍の記録密度を達成できる光磁気記録用OFH(Optical Flying Head)を実用化しました.OFHは青紫LD光を回折限界まで集光する高NAレンズ(NA:0.9)と高速磁界変調記録を可能とする薄膜コイルを,ハードディスクドライブ(HDD)に使用されているのと同等の浮上スライダ上に搭載した高性能光ピックアップです.このOFHと最新の高密度光磁気媒体とを組み合わせることにより50Gb/in^2以上の高密度記録を達成することが可能となりました.また,0FHの浮上量は約3μmで,現行HDDの約300倍あり,媒体交換が可能なリムーバブル装置を実現するほか,通常実験室で使用可能なOFH搭敏光磁気媒体評価設備(媒体テスク)の製品化も可能としました.

著者

大嶋 新太郎 伊達 政宗 三和 安次郎

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.28, no.4, pp.A1-A2, 2004-04-01

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All manuscripts except Guest Comments must include an abstract in English. The abstract must be a single paragraph containing no more than 200 words for Regular Papers, 150 for Letters, and 100 for Short Notes. The manuscripts should also include a list of key words in English. Key words appear after the English abstract under the heading of "Key words:" and should be separated by commas. Five to ten key words conveying the content of the manuscript should be selected from the main body of the manuscript and written in English. Key words should be entirely in lowercase characters except when they are typically written in uppercase characters or in abbreviated form.

著者

Choe Sug-Bong Shin Sung-Chul

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.25, no.3, pp.180-185, 2001-03-15

被引用文献数

2

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A magneto-optical microscope magnetometer (MOMM) has been developed to grab the domain reversal patterns in real time under applying a magnetic field, as well as, to simultaneously measure the local magnetic ptoperties with 400-nm spatial resolution.Using the system, the domain reversal behavior is revealed to change contrastingly between wall-motion and nucleation dominant with changing the multilayer structure of Co/Pd multilayers.From a quantitative analysis, the reversal ratio of the wall-motion speed over the nucleation rate is a governing parameter for the contrasting domain reversal dynamics.The activation volumes of the wall-motion and nucleation processes are found to be unequal, and the difference is closely ralated with the domain dynamics.Based on a Monte-Carlo simulation, both the macroscopic magnetic properties and the local magnetic variation are responsible for the contrasting domain reversal behavior.

著者

澤田 進

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.29, no.4, pp.371-372, 2005-04-01

著者

三浦 健司 村岡 裕明 杉田 愃 中村 慶久

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.24, no.4, pp.231-234, 2000-04-15

被引用文献数

38 34

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In perpendicular magnetic recording, medium noise is one of the crucial issues limiting the attainable density. The purpose of the reported work was to find a guiding principle for reducing the medium noise. Although previous work suggested that the media noise is caused by reversed domains in the bit cell, our time-domain noise measurements and a novel model using Voronoi cells suggest another noise origin : a noise source of transition irregularity caused by finite magnetic cluster size.

著者

池添 泰弘 茂木 邦雄 鈴木 隆史 廣田 憲之 植竹 宏往 渋谷 正徳 中川 準 北沢 宏一

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.23, no.4, pp.1557-1560, 1999-04-15

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We succeeded in making water levitate in air, using not an extreme by strong magnet such as a Bitter-type hybrid matnet, but a compact superconducting magnet. The levitated water ball had a spherical shape and levitated stably for over a day. We named this phenomenon "magneto-Archimedes levitation," because, to achieve it, we used gravitational and magnetic buoyancy forces in the presence of pressurized oxygen gas. In additon, our method enables paramagnetic substances to levitate in air, which has been considered to be impossible owing to the Maxwell relation, divB=0. We also succeeded in making paramagnetic aqueous copper sulfate levitate in air. To the best of our knowledge, this is the first demonstration of stable levitation of paramagnetic substances in the atmosphere.

著者

小塚 洋司

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.28, no.11, pp.1096-1102, 2004-11-01

参考文献数

13

被引用文献数

3

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-色即是空.空即是色.-629年,秋八月,唐の玄奘三蔵は,長安を発ち仏法を求めて天竺(インド)に赴く.空に飛ぶ鳥なく,地に走獣,水草もなし.熱砂のタクラマカン砂漠を徒行し,氷雪春夏にも解けずといわれる標高七千メートルに迫る天山山脈を踏破して,天竺に至る苦行は想像を絶するものであったという.玄奘三蔵ときに29歳であった.16年の歳月を経て長安に戻った玄奘は,般若心経をインド語の原典から中国語に翻訳する.上記はその一仏説である.さて,磁性電波吸収体の主材料であるフェライトは,加藤与五郎,武井武雨博士によって,我が国で発明された誇るべき電気電子材料である.銅一亜鉛系のソフトフェライトが初めて作製されたのは,昭和5年のことであった.しかし,当時の未発達なエレクトロニクス技術環境下では,その実用化への道のりは,苦難の旅立ちにも似た険しいものがあったと伝えられている.本橋では,ソフトフェライトを中心とする電波吸収体技術について,基礎事項から説き起こし,電波吸収材としてのフェライト,電波吸収特性を支配する透磁率特性などについて述べた後,新しい電波吸収体の考え方として,筆者が提案している材料定数等価変換法について紹介する.とくに,電波吸収原理について,上記仏教哲理を踏まえての解説を試みている.

著者

中村 健二 木村 幸四郎 一ノ倉 理

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.28, no.4, pp.602-606, 2004-04-01

被引用文献数

6

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A switched reluctance motor (SRM) has such desirable features as simple construction, high reliability, and low cost. The SRM has not, however, been put into wide application because of large torque ripple and acoustic noise. In addition, quantitative analysis and optimum design of the SRM have not been fully clarified. In a previous paper, we proposed a simple magnetic circuit model of an SRM based on its configuration. We calculated such dynamic characteristics of the SRM as excitation voltage, winding current, and flux in each part of the motor. In this model, however, reluctances of the stator and rotor cores are approximnated by a linear function. In order to improve the calculation accuracy, we have to consider nonlinear characteristics of the core material. Furthermore, local saturation occurring at stator and rotor pole-tips and leakage fluxes from the stator pole must be considered. In this paper, we examine a nonlinear magnetic circuit model of the SRM considering the local saturation at the pole-tips and the leakage fluxes.

著者

神宮寺 直子 山方 義彦 松木 英敏 星宮 望 古川 孝

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.21, no.4, pp.693-696, 1997-04-15

被引用文献数

6 2

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Cross coils that operate in an alternating magnetic field are proposed for transmitting signals. They cancel the noise induced by a symmetric magnetic field stem from a transcutaneous power-transmitting coil, and then transmit and detect the signals in the magnetic field. In comparison with figure-of-eight coils, cross coils keep a certain senditivity due to dislocation between the transmitting and detecting coils. The signal-transmitting ability of cross coils is not very high, but above properties make them useful as transcutaneous signal-transmitting coils.

著者

山口 正洋 薮上 信 中田 浩一 荒井 賢一 板垣 篤 板垣 喜一 斎藤 昇 布田 孝一 渡辺 光春 高橋 洋 田母神 隆 桜田 幸雄

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.22, no.4, pp.849-852, 1998-04-15

被引用文献数

3

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We developed a near-field magnetic noise mapping system by using a shielded-loop type coil array. High-resolution(01.mm)two-dimensional magnetic field vector detection was realized. We demonstrated a noise map of the loop antenna, microstrip line, and printed circuit board of a personal computer.

著者

山本 節夫 和田 宏文 栗巣 普揮 松浦 満 下里 義博

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.27, no.4, pp.363-366, 2003-04-01

被引用文献数

2 5

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A novel sputtering method using an electron-cyclotron-resonance (ECR) microwave plasma was used to perform reactive sputter-deposition of Ni-Zn ferrite thin films. Ni-Zn spinel ferrite thin films with preferential orientation of (400) and relatively low coercivity of 15 Oe were obtained at a high deposition rate of 14 nm/min. and at temperatures lower than 200 ℃. To achieve this high deposition rate, the configuration of the ECR sputtering apparatus and processing parameters such as the microwave input power, target voltage, and oxygen partial pressure were carefully optimized. Reactive ECR sputtering is one of the most suitable methods for preparation of ferrite thin films applicable to magnetic devices such as MMICs, isolators and circulators.

著者

山田 一 水野 勉 望月 大 渡辺 誠一

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.25, no.4, pp.1183-1186, 2001-04-15

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Mechanical technology makes wide use of the separation and transfer of non-magncticmaterialsinvariousproductionmanu魁tu.r一1ngproccsses,Th云spaFcrdcscribesthcfundarncntalsorprojcction,scparat10n,a11dl!ransrcrofalunlinumshcetsasnon-magnetic materials (for example aluminum disc), using a magnetic repulsion force, by means of a solenoid-type electromagnetic launcher. The key points of this paper are as follows: (1) Linear projection of Al discs. (2) Nonlinear projection of Al discs. (3) Nonlinear guide projection of Al discs.

著者

蔡 勝年 七原 正輝 水野 勉 山上 廣 山田 一

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.22, no.4, pp.937-940, 1998-04-15

被引用文献数

6 1 1

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This paper describes how the launch velocity of a solenoid-type electromagnetic launcher (EML) was simulated by combining the finite element method (FEM) with electric circuit and equation of motion, in order to improve the launch velocity of a projectile. The system constitution, the specifications of the projectile and solenoid coil, and the magnetizing curve of the carbon steel projectile are introduced, and methods for calculating the exciting current and launch velocity are derived. The inductance and the exciting current of the solenoid coil, the thrust, and the launch velocity of the projectile are simulatied. The simulation results for the dependence of the exciting current and the launch velocity on the time, and dependence of the launch velocity on the settled position are shown, and compared with the measured values. The calculation errors of the exciting current and the launch velocity with respect to the measured results are 3%, and 5%, respectively. These results confirm the feasibility of the simulation method.

著者

水野 勉 堀内 学 大橋 義納 西本 誉 小林 延行 加藤 耕明

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.30, no.2, pp.290-293, 2006-03-01

被引用文献数

2

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This paper describes the effect of the solenoid dimensions in an electromagnetic launcher on the height of projection. The height of projection is calculated by combining the circuit equation and the equation of motion. The magnetic force is carried by the finite element method. The calculation errors of the height of projection are respectively 5.5%. In conditions where the charging voltage V=68V and capacity C=3.66mF (input power W=8.46J), the height of projection of a solenoid with an outer radius r_0=19mm and length l=22mm reaches a maximum.

著者

工藤 高裕 高橋 康弘 高松 巌 涌井 伸二

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.30, no.3, pp.413-417, 2006-05-01

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This paper describes a robust design for a capacitance-drive-type linear electromagnetic solenoid (LES) using a quality engineering method and an exclusive dynamic analysis simulator. Reducing the variation in the performance significant by restrains the rise time of the current in the electromagnetic coil. In addition, the current should be kept above a specified level for a certain period. For this purpose, it is important to increase the inductance of the electromagnetic coil. In other words, it is necessary to increase the winding diameter and reduce the number of turns in order to reduce the variation in the performance. The validity of this robust design has been verified by experiments with actual solenoids. Consequently, it provides a high yield ratio.

著者

孝橋 昭生 小池 和幸

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.28, no.3, pp.193-199, 2004-03-01

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Recently high-resolution magnetic domain observation has been strongly required in both scientific and technological fields, because of the rapidly growing interest in the physics of nano-structured magnetic materials, the increasing recording density of conventional magnetic storage devices, and the advent of nano-scale magnetic and spin-electronic devices. In this respect, the spin-polarized scanning electron microscope (spin SEM) is a very useful instrument. It uses the phenomenon that the spin-polarization vector of secondary electrons emitted from ferromagnetic material is antiparallel to the magnetization vector at the point in the material from which the secondary electrons originate. It has several advantages such as high spatial resolution, no limitation on sample thickness and fiatness, magnetization information independent of the sample surface topography, and quantitative analysis of the magnetization vectors in three dimensions. In this review article, the principles and structure of spin SEM are briefiy explained, and data obtained with various spin SEMs are presented.

著者

仙道 雅彦 島崎 克彦 石山 和志 井上 光輝 荒井 賢一

出版者

公益社団法人日本磁気学会

雑誌

日本応用磁気学会誌 (ISSN:18804004)

巻号頁・発行日

vol.23, no.4, pp.1657-1660, 1999-04-15

被引用文献数

24

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The fundamental swimming properties of spiral-type magnetic micro-machines were investigated in detail by constructing four micro-machines with differnt structures. These micro-machines are able to swim in various liquids with kinematic viscosities ranging from 1.37 to 1000mm^2/s. This result suggests that the micro-machines have potential medical uses. In particular, they can swim against the stream in a liquid whose the velocity is comparable to the that of venous blood.