著者

西村 貴士 林 晃平 山田 外史 岩原 正吉

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:02850192)

巻号頁・発行日

vol.30, no.3, pp.387-390, 2006 (Released:2007-02-21)

参考文献数

7

---

It is important to understand leakage magnetic fields surrounding magnetic machines and devices for facilitation of development and evaluating the environmental effects of the magnetic field level to determine whether it conforms to the EMC guideline. The magnetic projection method is a measurement technique that can detect a leakage magnetic field by means of a simple probe. The principles of 2-D magnetic field measurement and reconstruction have been previously reported. This paper proposes the principles of a spherical magnetic projection method, and reports on an experiment carried out to observe the overall leakage magnetic field around a sample object. As a result, it is shown that the projection method can easily measure and visualize a magnetic field on a spherical surface with good accuracy.

著者

宮岡,千里

出版者

日本応用磁気学会

雑誌

日本応用磁気学会誌

巻号頁・発行日

vol.21, no.3, 1997-03-01

著者

伊良皆 啓治 N. Chaiyapoj 中西 徳昌 後藤 恵一 上野 照剛 小田原 成計 中山 哲 茅根 一夫 山崎 慶太

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:02850192)

巻号頁・発行日

vol.21, no.4_2, pp.805-808, 1997 (Released:2007-08-20)

参考文献数

7

被引用文献数

1 1

---

We have developed a multi-channel high-resolution SQUID magnetometer. This system consists of 12-channel pick-up coils 5 mm in diameter located on a 7.5 mm grid. The base-line of the gradiometer is 15 mm. The distance between the pick-up coil and the outside surface of the dewar is 5 mm. We measured the magnetic field produced by the activity of the orbicular muscle of eye, the magnetocardiogram produced by a human, and the magnetocardiogram produced by a rat. It is possible to obtain signals with good spatial resolution.

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

---

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

Sheng-bin HU Jiang-ling ZHANG Xiang-jun FENG Ya-xi GONG

出版者

(社)日本応用磁気学会

雑誌

日本応用磁気学会誌 (ISSN:02850192)

巻号頁・発行日

vol.15, no.S_2_PMRC_91, pp.S2_857-861, 1991 (Released:2011-12-15)

参考文献数

3

---

Based on the 4MB 3.5" Perpendicular Recording/Longitudinal Recording Floppy Disk Drive with a track density of 270 TPI, we further developed a 3.5" Perpendicular Recording Floppy Disk Drive demonstrating the potential to realize a capacity of more than 8MB capacity. The key technology included: (1) a Perpendicular Recording/Longitudinal Recording Floppy Head which was without erase element and helped realize the capacity of 4MB-8MB under the condition of without using servo system for tracking. (2) The GAL Technology to expand the Application-Specific Integrated Circuits. (3) The improvements of the read write channel.

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

---

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

---

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

---

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

桜井 秀也 青木 雅昭 宮本 毅信

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:02850192)

巻号頁・発行日

vol.14, no.2, pp.465-468, 1990-04-30 (Released:2007-12-03)

参考文献数

3

被引用文献数

1 1

---

In the last few years, MRI (Magnetic Resonance Imaging) has become one of the most excellent and important radiological and diagnostic methods. For this application, a strong and uniform magnetic field is required in the area where the patient is examined. This requirement for a high order of homogeneity is increasing with the rapid progress of tomographic technology. On the other hand, the cost reduction for the magnet is also strongly required. As reported in the last paper, we developed and mass-produced a permanent type magnet using high energy Nd-Fe-B material. This paper presents a newly developed 15 plane measuring method instead of a 7 plane method to evaluate the homogeneous field precisely. By using this analytical method and linear programing method, a new-shaped pole piece has been developed. In consequence, homogeneity was improved twice as much and the magnet weight was reduced 10% as compared with the formerly developed pole piece.

著者

鎌田 清孝 土井 俊哉 尾形 久直 賀戸 久 湯ノ口 万友 白樂 善則

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:02850192)

巻号頁・発行日

vol.24, no.4_2, pp.867-870, 2000 (Released:2007-02-26)

参考文献数

10

---

Environmental magnetic noises change with time influence biomagnetic measurements. There are two types: artificial magnetic noises, and those caused by natural fields For example, the former are caused by the movement of objects composed of magnetic materials, such as cars or trains, elevators, and fan-pumps of air conditioners, on the other hand, the latter are caused by natural fields, such as volcanoes or solar wind. The magnitude of geomagnetism is about 10 -4 T, and that of movements of cars or trains, elevators, and fan-pumps of air conditioners are 10-6 ∼ 10 -10 T. By contrast, the magnitude of magnetoencephalogram or magnetocardiogram is 10-12 ∼ 10 -14 T. Although they are, very weak, environmental magnetic noises cannot be ignored we measured the temporal vertical component of geomagnetic changes with a SQUID (Superconducting Quantum Interference Device) magnetometer in the vicinity of the crater of the Mount Sakurajima volcano for about 40 days. taken, By comparing our data taken by SQUID with the data of by the magnetic observatory of the Japan Meteorological Agency, we confirmed that our data are convincing. The influence of magnetic fluctuation caused by volcanoes on biomagnetic measurement is also discussed.

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

---

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

吉川 勲 岩坂 正和 上野 照剛

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:02850192)

巻号頁・発行日

vol.19, no.2, pp.597-600, 1995-10-01 (Released:2007-11-07)

参考文献数

26

被引用文献数

2 2

---

To ascertain the possible genetic effects of magnetic fields, the somatic reversion at the white locus and the somatic recombination mwh and fir genes in Drosophila melanogaster were examined quantitatively after lavae were exposed for 8 hours to static magnetic fields (8 T) or timevarying, sinusoidal magnetic fields (3.3 mT, 20 Hz). A static magnetic field of 8 T was effective in producing mosaic spots of eye color caused by intragenic mutation. The diagnosis according to statistical tests (Frei and Würgler, 1988) indicated a positive result under the testing conditions. Mosaic spots on the wing hairs caused by somatic recombination were slightly higher in the group exposed to static fields (8 T) than in the control group, but statistical analysis indicated a negative result. After exposure to time-varying magnetic fields (3.3 mT, 20 Hz), the mosaic spots of both types occurred with almost the same frequencies as in the control group.

著者

錦織,圭史

出版者

日本応用磁気学会

雑誌

日本応用磁気学会誌

巻号頁・発行日

vol.21(4-2), 1997-04-15

---

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

奥野 志保 橋本 進 猪俣 浩一郎 森本 せつ 伊藤 厚子

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:02850192)

巻号頁・発行日

vol.14, no.2, pp.213-216, 1990

被引用文献数

2

---

Amorphous Co-ferrite thin films not containing glass formers were prepared by ion beam sputter deposition. Their magnetic properties were invetigated by means of low field dc magnetization and ac susceptibility measurements, which gave evidence of spin glass behavior. Temperature dependence of magnetization in an external field of 50 Oe exhibited an irreversibility below nearly room temperature, which decreased with increasing field. A cusp corresponding to spin freezing temperature was observed at 284 K in ac susceptibility measured at 80 Hz, 1 Oe. Below this temperature, relaxation of thermoremanent magnetization was observed. Besides this transition at 284 K, a sharp peak which suggests another transition was observed at 86 K in ac susceptibility. It is considered that the spin glass ordering with a high spin freezing temperature is mainly caused by amorphousization for strong super-exchange interactions.

著者

永井 健三

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:02850192)

巻号頁・発行日

vol.1, no.2, pp.1-4, 1977-08-30 (Released:2010-05-18)

参考文献数

7

被引用文献数

1

著者

菊川 信吾 磯村 悟 岩田 聡 塩見 繁 内山 晋

出版者

The Magnetics Society of Japan

雑誌

日本応用磁気学会誌 (ISSN:02850192)

巻号頁・発行日

vol.7, no.2, pp.83-86, 1983

---

New bubble garnet films with orthorhombic anisotropy, (YTmGdBi)₃(FeGa)₅O₁₂, (YTmEuBi)₃(FeGa)₅O₁₂, (YTmSmBi)₃(FeGa)₅O₁₂ and (YTmLaBi)₃(FeGa)₅O₁₂, have been epitaxially grown on (110) GGG substrates. Although a large in-plane anisotropy <i>K</i>_p of 2∼4×10⁴ erg/cm³ is induced in YTmEu and YTmSm films, the uniaxial anisotropy <i>K</i>_u obtained is not large enough to be used for bubble materials. In YTmGd and YTmLa films, <i>K</i>_u is of almost the same magnitude as <i>K</i>_p with a value of 1.0∼1.5×10⁴ erg/cm³. The wall dynamics has been investigated by stripe domain transport method. For YTmLa films, the wall mobility μ is ∼22 m/sOe, the peak velocity <i>V</i>_p is ∼120 m/s and the coercive force <i>H</i>_c is ∼0.7Oe. These characteristics may be useful for current access devices.

著者

H. Tokumaru K. Arai S. Yoshimura K. Takizawa N. Uchida H. Yoshida

出版者

The Magnetics Society of Japan

雑誌

日本応用磁気学会誌 (ISSN:02850192)

巻号頁・発行日

vol.20, no.S_1_MORIS_96, pp.S1_323-328, 1996 (Released:2011-12-15)

参考文献数

5

---

The requirements for optical tapes in an optical tape recording system using a rotating optical head are presented. Along with the requirements, the best structure for a magnet-optical (MO) tape was studied. As a result, a tri-layer structure was adopted for easy production and the tri-layerd MO tapes were experimentally fabricated. Performances and problems of an MO tape were experimentally investigated using these samples. And, the following results were obtained which realized performances equal to an optical disk using a thin polyethylene terephthalate (PET) substrate. (1) The incidence of the laser is from the tri-layer side to avoid the birefringence of the PET substrate. (2) Surface roughness of the PET substrate is below Ra = 7 nm. (3) Heat-resistance of PET substrate makes recording or erasing operations in excess of ten thousand times possible. (4) MO tape (width: 1/2 inch, thickness: 10 μm) was stable in terms of optical and magnetic properties under a tape tension of 0.5 kgw. (5) Sufficient tape tension is necessary to satisfy the requirement of flatness since MO tape has a large extent of curling.

著者

小林 学 水野 浩司 水野 勉 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:02850192)

巻号頁・発行日

vol.21, no.4, pp.861-864, 1997-04-15

参考文献数

9

被引用文献数

9 3

---

This paper deals with the performance characteristics of a two-axis linear pulse motor (<i>X-Y</i> LPM) using air bearing. The mass, <i>M</i>, of the mover of <i>X-Y</i> LPM is 1.35 kg and the maximum static thrust, <i>F</i>_s, is 48.5 N with two-phase excitation at 2 A. The maximum velocity of the mover, <i>v</i>, is 1.4 m/s and the maximum acceleration, <i>a</i>, is 14.3 m/s² at a velocity of 1 m/s without any load. The kinetic thrust, Fk, is 19.3 N. A non-oriented magnetic steel sheet, 50A350, is used as the core in the mover, and rolled steel for general structures, SS400, is used as the stator. The maximum flux densities, <i>B</i>_m, of 50A350 and SS400 are 1.45 T and 0.123 T, respectively, in a magnetic field with a maximum intensity of 1 kA/m and at a frequency of 1 kHz. The material of the stator must have a high magnetic flux density at the driving frequency to achieve high velocity and high-thrust driving of the <i>X-Y</i> LPM.

著者

槙 智仁 広沢 哲

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:02850192)

巻号頁・発行日

vol.31, no.3, pp.189-192, 2007 (Released:2007-05-31)

参考文献数

7

被引用文献数

1 1

---

The magnetization mechanism of an Nd-Fe-B HDDR magnet was studied by measuring its recoil curves. When compared with those of isotropic Nd-Fe-B sintered, HDDR, and melt-spun magnets, the behavior of the recoil curves of the HDDR magnet was similar to that of the recoil curves of the melt-spun magnet. This means that the isotropic HDDR magnet behaved like single-domain particles. In addition, calculated isotropic recoil curve that assumes only rotation of the magnetization of single-domain particles showed the same tendency as the recoil curves of the HDDR magnet. This result indicates that the recoil curves of an isotropic HDDR magnet were dominated by rotation of the magnetization, and were not significantly influenced by domain wall movement. Moreover, the recoil curve of an anisotropic HDDR magnet behaved similarly to calculated anisotropic recoil curve based on the rotation of the magnetization of single-domain particles with an orientation distribution. This means that the recoil curves of an anisotropic HDDR magnet were also dominated by rotation of the magnetization. These results suggest that the HDDR magnet behaved like single-domain particles in its recoil curves, which were dominated by rotation of the magnetization and were not significantly influenced by domain wall movement.

著者

薮見 崇生

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:02850192)

巻号頁・発行日

vol.31, no.1, pp.23-30, 2007 (Released:2007-05-31)

参考文献数

6

被引用文献数

5

---

EPS (Electric Power Steering) enables an increase in automotive fuel efficiency by 3-5% and contributes to the protection of the environment by eliminating the oil medium used in conventional hydraulic power steering. For this reason a sharp increase in demand for EPS is expected. Permanent magnet motors are generally used for EPS but a reduction of cogging torque in these motors is one of the challenges we face to ensure safe and comfortable vehicle handling. In this paper, magnetic field analysis was conducted on brushless motors with radially oriented ring magnets to find effective ways to reduce cogging. Through the investigation of the relationship between coercive force distribution and magnetizing waveform, it was confirmed that the following methods were effective in reducing the cogging torque.(1) Optimization of the skew magnetization angle according to the coercive force distribution along the axial direction of the magnet.(2) Control of the magnetizing intensity along of the circumferential direction of the magnet.