著者

富田 宏 宮島 英紀 近角 聡信 竹屋 浩幸 武居 文彦

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.13, no.2, pp.469-472, 1989-04-30 (Released:2007-12-07)

参考文献数

6

被引用文献数

2 2

---

The magnetic flux pinning in a superconducting Y1Ba2Cu3Oy single crystal and polycrystal has been investigated in magnetic fields up to 8 kOe using torque magnetometry. The magnetic torque curve shows an anisotropic rotational hysteresis loss. The results are interpreted in terms of anisotropic flux pinning and creeping effect.

著者

稲葉 信幸 宮島 英紀 武富 荒 近角 聡信

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.13, no.2, pp.245-248, 1989-04-30 (Released:2007-12-07)

参考文献数

4

被引用文献数

2 2

---

Magnetization (M), field induced magnetic anisotropy (Ku), rotational hysteresis loss (Erot) and melting point (Tm)f water- and paraffin-base ferrofluids were investigated in a temperature range from 77 K to 300 K as a function of the density of colloidal particles. Both paraffin and paraffin-base fluids were melted down at the temperature range from 180 to 210 K. In this range, the values of M and Erot, for paraffin-base fluids increased and Ku decreased with increasing temperature. These properties are interpreted by assuming that liquid-state and solid-state parts in paraffin exist in this tempetarure range and that the volume of solid-state part decreases with increasing temperature. The freezing point depression was observed in water-base fluids.

著者

稲葉 信幸 宮島 英紀 武富 荒 近角 聡信

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.12, no.2, pp.283-286, 1988-04-30 (Released:2007-12-07)

参考文献数

6

被引用文献数

5 3

---

The magnetization process of a ferrofluid whose carrier fluid is paraffin was investigated in a temperature range from 77K to 300K as a function of the intensity of cooling field and the freezing rate. Phase transition between liquid state and solid state can be simulated by using the ferrofluids as a magnetic probe. The uniaxial magnetic anisotropy was induced by field cooling in frozen ferrofluids. This induced anisotropy decreased with increasing temperature near the melting point and disappeared at 30K higher temperature than the melting point. In this region the rotational hysteresis was observed. The anisotropy constant K near the melting point was described by the equation K=A·exp(ΔEK/kT). The value of the activation energy ΔEK was almost the same as that of ΔEη estimated from the viscosity vs. temperature relation η∝ exp(ΔEη/kT).

著者

武富 荒 小川 伸一 宮島 英紀 近角 聡信

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.12, no.2, pp.263-268, 1988-04-30 (Released:2007-12-07)

参考文献数

20

被引用文献数

14 16

---

Magnetooptical effect of magnetic fluids is investigated. The phase difference θ between the ordinary ray and the extraordinary ray which are transmitted through the magnetic fluid thin film was found to be described in the functional form θ1f(H)/[T-T1+f(H)], where H is the magnetic field applied to the magnetic fluid thin film, T is the absolute temperature of the film, f(H) is a certain increasing function of H and T1, θ1 are the positive constants. The field dependence of light transmissivity of magnetic fluid thin films is well described by the cluster model of ferrous colloidal particles in the applied field direction when the aggregation is small. The field dependence of transmissivity is, however, interpreted neither by the electric absorption of the clusters nor by the Rayleigh scattering when the cluster becomes larger. The diffraction effect by the linear clusters directed to the applied field must be taken into account in interpreting the light extinction.

著者

茅 誠司

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:02850192)

巻号頁・発行日

vol.1, no.3, pp.1-4, 1977-11-30 (Released:2010-05-18)

著者

宮原 将平

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.2, no.2, pp.29-32, 1978-05-31 (Released:2010-05-18)

著者

近角 聰信

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.3, no.2, pp.39, 1979-05-31 (Released:2010-05-18)

著者

開道 力

出版者

公益社団法人 日本磁気学会

雑誌

Journal of the Magnetics Society of Japan (ISSN:18822924)

巻号頁・発行日

vol.34, no.3, pp.356-361, 2010-05-01 (Released:2010-05-28)

参考文献数

14

---

This paper discusses the possibility of realizing improvements in magnetic properties of non-oriented electrical steel sheets. In such sheets, a random {100} texture can increase flux densities and decrease iron losses, and the increase in flux density at 5000 A/m (B50) may be over 0.2 T, while decrease ratio of iron loss at 1.5 T and 50Hz (W15/50) may be more than 1/3. On the other hand, the improvement of iron loss at 1 T and 400Hz (W10/400) due to a random {100} texture may be little, but the texture can increase flux densities, and the increase in flux density at 800 A/m (B8),where motors are designed, may over 0.4 T. It is important to improve metallurgy and rolling technology in manufacturing process in order to realize the theoretical optimum magnetic properties of non-oriented electrical steel sheets.

著者

藤田 浩一 張 濤 井上 明久 牧野 彰宏

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.22, no.4_2, pp.381-384, 1998 (Released:2007-06-29)

参考文献数

8

---

New Fe-based amorphous alloys exhibiting the glass transition and supercooled liquid region before crystallization were searched for in the composition range of Fe63Co7Nd10-xZrxB20 (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, Js of 1.15 to 1.18 T, Jr 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.

著者

山崎 慶太 奥田 清明 阿部 隆之 内川 義則 志村 徹 小谷 誠

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.16, no.6, pp.769-774, 1992-12-01 (Released:2013-01-11)

参考文献数

7

被引用文献数

6 7

---

This paper describes the design and the development of a prefabricated magnetically-shielded-room (PMSR) of the hexagonal type for high sensitive measurement of neuro-magnetic fields such as magnetoencephalography (MEG) mainly using SQUIDs with first and/or second-order gradiometers. This PMSR consists of prefabricated plywood panels 1.2 m wide×2.4 m high×24 mm thick. It covers a floor area of about 9 m2. The panel is sandwiched by two layers of high-μ metal sheets 1 mm thick. The shielding factor at the center of PMSR against the external magnetic field is 20 to 40 dB in the range of DC to 120 Hz. Magnetic noise inside PMSR measured by a second-order gradiometer was less than hundreds fT above 0.5 Hz excepting 50 Hz. In this case, a second order gradiometer was able to eliminate the common mode magnetic noise of about 20 Hz, which was essentially observed by a magnetometer, caused by the vibration of PMSR. These results were discussed and compared with the calculations.

著者

木原 隆幸 小野 寛太 奥田 太一 原沢 あゆみ 尾嶋 正治 横尾 篤 木下 豊彦

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.25, no.4_2, pp.1059-1062, 2001 (Released:2007-02-02)

参考文献数

11

被引用文献数

2 3

---

The magnetic properties of thin films with reduced lateral dimension are significantly different from those of materials in the bulk state, and have provided a wealth of scientific interest and potential technological applications. It is therefore very important to study magnetism in microstructures or small magnetic domains, and one of the most powerful tools for investigating such magnetism is the photoelectron emission microscope with synchrotron radiation as its light source (SR-PEEM).We report in this paper our set-up of a new SR-PEEM system, and present the preliminary results.

著者

大友 祐一 薮上 信 加藤 和夫 小澤 哲也 荒井 賢一

出版者

公益社団法人 日本磁気学会

雑誌

Journal of the Magnetics Society of Japan (ISSN:18822924)

巻号頁・発行日

vol.33, no.3, pp.283-286, 2009-05-01 (Released:2009-05-21)

参考文献数

5

被引用文献数

2 2

---

We developed a very sensitive high-frequency carrier-type magnetic-field sensor with a sub-pT resolution using a transmission-line-type sensor. Meander-type sensor elements using amorphous CoNbZr films (4μm in thickness), Cu conductor with a meander pattern (30 mm in length, 1.0 mm in width, 18 μm in thickness), and a ground plane were fabricated. We obtained a magnetic field resolution of 9.1×10-13 T/Hz1/2 at 1 Hz. The detectable magnetic field was limited by the 1/f noise. We detected a magnetocardiogram (MCG) signal of heartbeats with the sensor.

著者

小澤 哲也 山田 洋 佐藤 弘二 小島 健 薮上 信 小林 伸聖 中居 倫夫 荒井 賢一

出版者

公益社団法人 日本磁気学会

雑誌

Journal of the Magnetics Society of Japan (ISSN:18822924)

巻号頁・発行日

vol.37, no.1, pp.1-7, 2013-01-01 (Released:2013-01-08)

参考文献数

12

被引用文献数

10

---

We report the results we obtained from applying a magnetic system to detect cracks using a thin film magnetic field sensor to measure the hole of aluminum. The thin film magnetic field sensor consisted of a coplanar line and amorphous CoFeSiB film. The main characteristic of the sensor is that the phase of the carrier signal changes when a magnetic field is applied. The sensitivity of the developed sensor was 70 deg./Oe. We used the thin film magnetic field sensor in an experiment to measure leakage magnetic flux from the surface of the aluminum while applying an AC magnetic field to the aluminum. The surface of the aluminum was scanned by an electric stage with a motor. The phase value of the sensor was converted to a voltage value, and then measured with a lock-in amplifier. As a result, the hole of aluminum was detected by measuring the distribution of the leak magnetic flux on the aluminum surface.

著者

薮上 信 加藤 和夫 加茂 芳邦 小澤 哲也 荒井 賢一

出版者

公益社団法人 日本磁気学会

雑誌

Journal of the Magnetics Society of Japan (ISSN:18822924)

巻号頁・発行日

vol.32, no.4, pp.483-486, 2008-07-01 (Released:2008-07-18)

参考文献数

7

被引用文献数

1 1

---

We developed a very sensitive high-frequency carrier-type magnetic field sensor with a pT resolution using a transmission-line-type sensor. Meander-type sensor elements using amorphous CoNbZr films were fabricated. We obtained a magnetic field resolution of 3.0 x 10-12 T/Hz1/2 at 1 Hz. The detectable magnetic field was limited by the 1/f noise. We detected the magnetocardiogram (MCG) signal by using the sensor.

著者

千田 正勝 武井 弘次 石井 修 越本 泰弘 戸島 知之

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.465-468, 1995-04-01 (Released:2007-11-07)

参考文献数

13

被引用文献数

4 4

---

This study reports on the performance of a thin-film magnetic sensor that uses impedance change at a high frequency. A closed magnetic circuit, a strip pattern for the magnetic films, and an NiFe/SiO2 multilayer film structure were adopted for high sensitivity and large voltage change. A voltage change ratio of 50-60% was achieved by applying an external field of several Oe with an AC carrier of ∼800 MHz. The sensor was confirmed to perceive a highfrequency external field as an amplitude modulation of the AC carrier voltage, and exhibited broad frequency bandwidth, high linearity, and no hysteresis or Barkhausen noise.

著者

小澤 哲也 馬渡 宏 薮上 信 石山 和志 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:02850192)

巻号頁・発行日

vol.29, no.8, pp.831-837, 2005 (Released:2007-05-10)

参考文献数

5

被引用文献数

2 2

---

The impedance and phase characteristic of a magnetic thin film changes when a magnetic field is applied. The high-frequency-carrier magnetic field sensor, also called a GMI sensor, employs this phenomenon as its principle. We directed our attention to the change in the phase characteristic, and measured the dc magnetic field by measuring the phase as a phase difference, using the dual-mixer time-difference method. We optimized the method and the continuous sampling condition to measure the phase difference, and developed an efficient system for measuring the continuous sampling phase difference with low noise. The system was successfully used to measure the ac magnetic field by continuous sampling of the phase difference of a high-frequency-carrier magnetic field sensor.

著者

内山 剛 山口 明啓 内海 裕一

出版者

公益社団法人 日本磁気学会

雑誌

Journal of the Magnetics Society of Japan (ISSN:18822924)

巻号頁・発行日

vol.34, no.4, pp.533-536, 2010-07-01 (Released:2010-07-13)

参考文献数

7

---

In this experiment, we investigated noise characteristics of a pulse magneto-impedance sensor which is based on an amorphous magnetic wire with a pickup coil. For a helical static magnetization, the ac current i passing the wire induces a coil voltage Vc in the coil around the wire. The pulsed excitation, combining both high and low frequency harmonic, produces the voltage Vc with dc current biasing. We describe improvements of pulse excitation conditions for an amorphous magnetic wire to reduce magnetic noises. The relation between the time interval of a current pulse train T and magnetic noises was investigated. The magnetic noise is suppressed clearly when T is smaller than 1.5 μs for pulse width 10 ns. Under the optimal conditions, the rms noise of 1-cm-long an amorphous wire magneto-impedance sensor with 600 turns of the pickup was estimated as 1pT/Hz1/2M at 20 Hz∼500 Hz.

著者

片根 保

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.22, no.4_2, pp.789-791, 1998 (Released:2007-06-29)

参考文献数

12

---

The effects of dc magnetic fields on animals and plants have been studied for a long time. In particular, many studies of the effects on plants have been reported, because of the ease with which experiments can be controlled. However, it is still not clear whether dc magnetic fields have any influence on plants. This study shows the effects of both horizontal and vertical dc magnetic fields on the growth of Japanese radishes. A dc magnetic field plays a role in restricting the initial growth of radishes, and the growth and root hair are also affected by the direction of the magnetic field.

著者

中村 基訓 木村 道哉 末岡 和久 武笠 幸一

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.24, no.4_2, pp.771-774, 2000 (Released:2007-02-26)

参考文献数

14

被引用文献数

2 2

---

A variety of techniques have been proposed to measure surface magnetic properties using scanning probe microscopy. The most widely used is magnetic force microscopy (MFM). In many cases, however, it is hard to analyze MFM data quantitatively. A magnetoresistive (MR) device is also a candidate for such a sensor that can operate at room temperature with high sensitivity. Yamamoto et al. have demonstrated a scanning magnetoresistance microscope (SMRM) using a commercially available MR read-head for a hard disk. Since they held the MR head on a slider, there was no feedback system to control the distance between sample and sensor. We made a cantilever for the MR sensor to get the surface topography and magnetic properties simultaneously. Its magnetic field sensitivity with 10-mA sensing current is 90 μV/Oe, and our roughly estimated minimum field resolution is a few mOe (only Johnson noise is assumed with 10-kHz bandwidth at room temperature), which is much better than that of a scanning Hall probe microscope.

著者

内山 剛 牧野 正義 毛利 佳年雄

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:02850192)

巻号頁・発行日

vol.16, no.3, pp.556-559, 1992-06-01 (Released:2013-01-11)

参考文献数

3

被引用文献数

2 2

---

A transistor logic memory module based on the Royer oscillator type magnetic multivibrator is presented, in which a HTcSC thin disk core having six coils tightly set around it is connected with two switching transistors. The oscillation of this module is initiated by applying a pulse current to a coil and the phase of oscillation is controlled by the sign of the trigger pulse. That is, this module is a phase memory type logic device such as Parametron. Moreover, oscillation is terminated by applying a pulse current to a small transistor which shorts another coil of the HTcSC. We can assign two oscillating states with different phases to the numerical values ±1 and the non-oscillating state to 0. This logic is decided by a majority of multi-input, so that this module has applications in the field of neural network system.