IEEJ Transactions on Fundamentals and Materials
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
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Volume 132, Issue 10
Displaying 1-24 of 24 articles from this issue
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Special Issue (I) on Fabrication and Evaluation of Nanoscale Magnetic Materials with New Functionality
Special Issue (II) on Instrumentation and Measurement Technology Supporting Technological Innovation
Special Issue Paper (I)
  • Magnetic Relaxation of Magnetic Nanoparticles Dispersed in Solution under High Frequency Magnetic Field
    Koji Ueda, Asahi Tomitaka, Tsutomu Yamada, Yasushi Takemura
    2012 Volume 132 Issue 10 Pages 813-817
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.813
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    Magnetic nanoparticles are heated by an applied ac magnetic field, which leads to their use as hyperthermia agents, and the applications of magnetic nanoparticles were reported. In this study, the self-heating property of magnetic nanoparticles dispersed in solution was evaluated by measuring hysteresis loop and susceptibility spectra under ac magnetic field.
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  • Easy Axis Orientation of Nd-Fe-B Melt-spun Magnets Caused by Hot-rolling
    Masaaki Takezawa, Toshio Mihara, Yuji Morimoto, Jiro Yamasaki, Masaaki ...
    2012 Volume 132 Issue 10 Pages 818-821
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.818
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    The c-axis orientation of Nd-Fe-B melt-spun ribbons caused by hot-rolling was investigated. A small roll is added on a steel wheel near a quartz tube in such a way that melt-spun ribbons are hot-rolled immediately after quenching. X-ray diffraction patterns measured on both surfaces of the ribbons indicate that the c-axis is oriented normal to the ribbon plane. A domain pattern at the surface of the ribbons was observed with a Kerr microscope. Most of the grains exhibit maze domain configurations indicating the c-axis orientation normal to the ribbon plane. This suggests that hot-rolling promotes the c-axis orientation of Nd-Fe-B melt-spun ribbons.
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  • Control of Magnetic Moment in Uniaxial Anisotropy Magnetic Thin Film Taking Leakage Flux in RF Planar Spiral Inductors with Closed-Magnetic Core into Account
    Makoto Sonehara, Kenji Ikeda, Toshiro Sato
    2012 Volume 132 Issue 10 Pages 822-826
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.822
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    A relation between high-frequency properties and an angle θ of anisotropy magnetic field in CoFeSiO/SiO2 multilayer nano-granular magnetic film for an RF planar spiral inductor was described in order to suppress a leakage flux. A ferromagnetic resonance (FMR) frequency fr and an FMR half-width Δfr were very little dependence on θ. The FMR frequency fr and the FMR half-width Δfr were estimated about 2.5 and 0.3 [GHz]. On the other hand, the static permeability μs was dependent on approximately sin2θ. The static permeability in hard axis μh was estimated about 250. So then, the CoFeSiO/SiO2 multilayer nano-granular magnetic film has superior high frequency character for the inductor.
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  • TMR of Metal-insulator Nano-granular Thin Films and Power-saving Magnetic Sensor GIGS®
    Nobukiyo Kobayashi, Tsuyoshi Masumoto
    2012 Volume 132 Issue 10 Pages 827-832
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.827
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    The structure and tunnel magneto-resistance of (Fe-Ni or Fe-Co)-(Mg-F) nano-granular thin films were investigated. The films were prepared by a tandem deposition method, using Fe-Ni or Fe-Co alloy and MgF2 insulator targets. A granular structure was found to be consisted of Fe-Ni or Fe-Co based nano-granules surrounded by thin intergranules of Mg based fluoride which were crystallized with a MgF2 structure. These films show tunnel-type magnetoresistance which is caused by the film structure. The GIGS® (Granular-in-Gap-Sensor) consisting of the (Fe-Co)-(Mg-F) nano-granular thin film filled into a narrow gap of soft magnetic a-CoFeSiB thin film was prepared. GIGS® has large electrical resistance (10kΩ-10MΩ) because of high electrical resistivity of metal-nonmetal nano-granular film. The large electric resistivity causes the reduction of the electricity consumption.
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  • Study on Monolithic Structure and Multiaxis Magnetic Sensing with Magnonic Crystals
    Hiroyuki Takagi, Josho Noda, Tomomi Ueno, Naoki Kanazawa, Yuichi Nakam ...
    2012 Volume 132 Issue 10 Pages 833-837
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.833
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    We aim the development of the high sensitive magnetic sensor with magnonic crystals at room temperature. In this study, we fabricated a SmCo thin film magnet on magnonic crystals as monolithic structure. We could excite the spin wave and develop the magnonic band gap by magnetic field of the thin film magnet. On the other hand, magnonic crystals have high magnetic field dependence so we think that it will use for a magnetic sensor. The result, maximum response sensitivity of the magnonic crystals with SmCo thin film magnets becomes 7,900%/Oe. Additional, we studied 2-axis magnetic field sensing by spin wave.
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  • Pulse Rise Time Dependence of Switching Field of Co/Pt Multilayer Dot
    Nobuaki Kikuchi, Yoshihiro Suyama, Satoshi Okamoto, Osamu Kitakami
    2012 Volume 132 Issue 10 Pages 838-843
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.838
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    A voltage pulse generator for magnetic field application was built using a coaxial cable as a capacitor. The pulse duration was fixed to 10ns and the pulse field rise time was controlled from 70ps to 4ns using a low pass filters. Magnetization switching experiments have been carried out on a Co/Pt multilayer dot with diameter of 300nm using perpendicular pulse fields. The required pulse field amplitude for magnetization switching is independent of the pulse rise time suggesting the thermally activated process is dominant in the perpendicular field geometry.
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  • Isotropic Nd-Fe-B Thick-film Magnets Applied for Micro-rotors Prepared by PLD Method
    Masaki Nakano, Masaru Itakura, Takeshi Yanai, Fumitoshi Yamashita, Hir ...
    2012 Volume 132 Issue 10 Pages 844-848
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.844
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    The flexibility of magnetization of isotropic thick-film magnets enabled us to enhance the torque of a millimeter-size motor comprising a multi-polar magnetized rotor compared to the torque of a miniaturized motor using an anisotropic Nd-Fe-B sintered magnet. In order to upgrade the torque of the small motor further, increase in the remanence value of the isotropic films is indispensable. In this study, therefore, we prepared nano-composite Nd-Fe-B thick-films by using a high-speed PLD (Pulsed Laser Deposition) method with the deposition rate of approximately 40μm/h. Resultantly, use of additive (Zr or Nb) was effective to enhance the coercivity value of Nd-Fe-B thick-film magnets with Nd-poor composition, however it was difficult to increase the values of remanence. In order to apply the thick films to a micro-rotor, investigation on several experiments related to mechanical property was also carried out.
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Special Issue Paper (II)
  • Suppression of Weather Clutter by Means of Log-normal/CFAR Circuit Modified CA LOG/CFAR Circuit
    Shuji Sayama, Seishiro Ishii
    2012 Volume 132 Issue 10 Pages 849-856
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.849
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    We have observed weather clutter including targets (ships) using an S-band radar with a frequency of 3.05GHz, a beamwidth of 1.8°, and a pulsewidth of 0.5μs. To investigate the weather clutter amplitude statistics, we introduce the Akaike Information Criterion (AIC). We have found that the weather clutter amplitudes obey the log-normal, Weibull, and log-Weibull distributions with the shape parameters of 0.329 to 0.477, 4.40 to 4.55, and 11.93 to 16.44, respectively, for data within the beam width of an antenna. We have proposed the log-normal/CFAR circuit which is modified a Cell-Averaging (CA) LOG/CFAR circuit. It is found that weather clutter is suppressed with improvement of 51.58dB by log-normal/CFAR.
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  • A Novel Background Subtraction Method for Moving Vehicle Detection
    Xiaofeng Lu, Takashi Izumi, Lin Teng, Tadahiro Horie, Lei Wang
    2012 Volume 132 Issue 10 Pages 857-863
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.857
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    Background subtraction is a method typically used to segment moving vehicles in image sequences taken from a static camera by comparing each new frame with a model of the background scene. This paper presents a robust background subtraction algorithm which reduces the influence of illumination changes and shadows and adapts to rapid changes in the traffic scene. A statistical background modeling method is presented, which is based on a histogram at the pixel level and produces a color model from a series of frames. For foreground detection, we propose the Choquet integral to fuse the three color-component similarity measures and a texture similarity measure based on a uniform local binary pattern. Finally, we propose a new adaptive background maintenance method. The experimental results for several dataset videos show that the proposed method is more efficient, robust, and accurate than classical approaches.
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  • Evaluation of Spatial Resolution of Nondestructive Testing of Thermal Barrier Coating by Terahertz Imaging
    Tetsuo Fukuchi, Norikazu Fuse, Mitsutoshi Okada, Tomoharu Fujii, Maya ...
    2012 Volume 132 Issue 10 Pages 864-870
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.864
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    The spatial resolution of THz imaging in nondestructive testing of thermal barrier coating was evaluated. The instrumental resolution was evaluated using a test pattern and was found to be about 0.6mm. The test pattern under a YSZ sample of thickness 1.25mm could be identified from the spatial distribution of the wave reflected from the back side of the YSZ sample, with a planar spatial resolution of about 1mm. THz imaging successfully detected an artificial defect of 1mm×1mm under the topcoat in a TBC sample. The results showed the possibility of detection of surface defects under the topcoat by THz imaging.
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  • A Study on Measurement of Frequency Characteristics of the Super-high Frequency Crystal Resonator
    Yukinori Sakuta, Mitsuhiro Watanabe, Takeshi Imaike, Yoshifumi Sekine
    2012 Volume 132 Issue 10 Pages 871-877
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.871
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    The progress of the fabrication technology of the crystal resonators became to expand to VHF and UHF band beyond a traditional HF band. Along with this fact, the characteristic of the crystal resonators is demanded to be measured in these frequency bands. An international standardized measurement method, however, do not exist now. In these frequency range, all of devices and circuits work as distributed constant circuit. When we measure the characteristic of the crystal resonator, it is necessary to consider the setting portion of the crystal resonator on circuit as the distributed constant circuit. We have examined the use of the microstrip line to measure the characteristic of the crystal resonator.
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  • Evaluation of Mental Workload on Repetitive Handwriting Process
    Masafumi Uchida, Asami Matsutani, Akio Nozawa
    2012 Volume 132 Issue 10 Pages 878-885
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.878
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    Today is the information society and handwriting is reconsidered and adopted for various systems, for example, authentication systems and input systems. In this paper, MWL (Mental Work Load) and iterative process of stroke based on the characteristics of human rhythm perception and the relationship between them was examined. Specifically, the period of ISI draw stroke and some continuous synchronous repetitive auditory stimuli (complex tasks such as synchronous tapping and drawing and stroke) in a process set out by using various and repetitive stroke times such as SE, IWI, IE, WE and SWE was examined. In addition, in order to propose a new experimental system, the parameters that reflect the structure of the process related to the stroke mechanism during the repetitive SWE process were identified. Finally in order to pay a further attention to the consumed resources, the dynamics of SWE, MWL and the related physiological, psychological and performance indicators were compared.
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  • Amplitude Statistics of Sea Clutter by MDL Principle
    Shuji Sayama, Seishiro Ishii
    2012 Volume 132 Issue 10 Pages 886-892
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.886
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    We have observed sea clutter using an X-band radar with a frequency of 9.41GHz, a beamwidth of 1.0°, and a pulsewidth of 0.5μs. To investigate sea clutter amplitude statistics, we introduce four probability distribution models and the Minimum Description Length (MDL) principle, which is more rigorous comparison between the distributions than the Akaike Information Criterion (AIC). We have found that the sea clutter amplitude obey the generalized gamma distribution with the shape parameter of α=3.54 for entire data and the log-normal, Weibull, log-Weibull, and generalized gamma distributions with the shape parameters of σ=0.467, c=2.86 to 3.39, c=9.37 to 10.76, and α = 2.52 to 4.18, respectively, for data within the beam width of an antenna. The number of best fit of the log-normal, Weibull, log-Weibull, and generalized gamma distributions to data are 1, 2, 2, and 18, respectively.
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  • Research into Warning Time Optimum Control for Level Crossing
    —Train Location Detector using Three-Inductive Wires—
    Taiyo Matsumura, Takashi Ono
    2012 Volume 132 Issue 10 Pages 893-900
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.893
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    At present, there are a variety of measures that are being taken in the face of the lengthening of level crossing closure times, but since these all rely on the intermittent detection of the location and speed of the train, they have not yet shown sufficient effectiveness. Against this backdrop, we will show in our simulation and experimental result the use of inductive wires to continuously detect the location of the train, while also outlining the crossing warning time control system, and how the application of this system. In this paper, warning time optimum control for level crossing with a continuous type train location detector using crossed inductive wires will be proposed and its effect to shorten crossing warning times will be discussed. And we have also confirmed the feasibility of the bidirectional information flow method. As a result, we have demonstrated that the proposed method is effective in delaying the timing of the initiation of warning and it is applicable to a high speed train.
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  • Proposal for Short Optical Pulse Generator with Low Time Jitter for Monitoring Optical Signal Quality
    Shigeo Arai, Akihito Otani, Koji Nonaka
    2012 Volume 132 Issue 10 Pages 901-906
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.901
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    An optical performance monitor (Q-monitor) based on all-optical sampling technology has been reported as an optical signal quality monitor for photonic networks. The Q-monitor measures the eye pattern of the optical transmission signal, and the signal quality is assessed by calculating the Q factor from the measured eye patterns. Here, we propose a short optical pulse generator with low time jitter as an optical sampling pulse source for the Q-monitor. It consists of an optical pulse source, a pulse compressor, and a waveform shaper. We confirmed that the pedestal-suppressed pulse was obtained using the pulse shaper, and that optimizing the pulse generator operating conditions produced a pulse width of 7.0 ps when the RMS time jitter was less than 0.5 ps. The eye pattern is clear for a 10-Gb/s NRZ signal using a Q-monitor with the short optical pulse generator. This paper explains the pulse generator principle and performance. Furthermore, we report evaluation results for the Q-monitor with pulse generator.
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  • Nondestructive Evaluation Method for Pearl Nucleus using Optical Properties
    Eiichiro Momma, Ginji Takagi, Satoshi Kurumi, Kaoru Suzuki, Takashi On ...
    2012 Volume 132 Issue 10 Pages 907-912
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.907
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    This study aims to establish a method of an automatic nondestructive evaluation of a pearl nucleus. In this paper, we examined a distinction of a material of the pearl nucleus using optical properties and an evaluation of quality using image processing about the pearl nucleus made of mussel shell. As a result, it is clarified that the nondestructive evaluation of the pearl nucleus was possible by our method.
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  • Study on an Evaluation Method of Platinum Resistance Thermometers Used in the Stationary Air
    Kazuaki Kodaira
    2012 Volume 132 Issue 10 Pages 913-919
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.913
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    An evaluation method of platinum resistance thermometers (PRTs) used in the stationary air was considered. A comparison measurement apparatus to evaluate PRTs was developed by using a commercially available temperature bath and the performance of the apparatus was evaluated. The apparatus has high temperature stability and good temperature distribution although the thermal medium is the air. The uncertainty of the apparatus is less than 1mK. A PRT was evaluated for a trial with this apparatus at 23°C. First, a PRT that was set in the water was measured with a Standard Platinum Resistance Thermometer (SPRT) in the temperature bath. Next, the identical PRT was set in the air chamber of the developed apparatus and measured with the SPRT. And, each result was compared. As a result, it was possible to distinguish the difference of behavior of the PRT at different environment by a proposed method in this study. And, it was confirmed that the cause of different behavior was the self-heating of the PRT.
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  • Anomalous Relaxation in Magnetoresistance of Fe/Fe-O Granular System
    Hiroshi Sakuma, Tomoyasu Taniyama, Kiyoshi Ishii
    2012 Volume 132 Issue 10 Pages 920-923
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.920
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    Fe/Fe-O granular thin films were fabricated by gas flow sputtering. Transmission electron microscopy analysis reveals that α-Fe granules are surrounded by a matrix consisting of tiny crystallites of Fe3O4 and/or γ-Fe2O3. The matrix acts as a tunnel barrier for electrical conductance. The Fe/Fe-O granular thin film exhibits an anomalous response to magnetic fields at low temperatures. When a magnetic field is applied, the resistance decreases. After the field is settled, the resistance increases for more than 1800s. A possible mechanism for the anomalous relaxation is the relaxation of the spins in the spin-glass-like Fe-O matrix.
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  • Two-stage Inductive Voltage Divider using Special Winding Method
    Shintaro Tsutsumi
    2012 Volume 132 Issue 10 Pages 924-929
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.924
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    Inductive voltage dividers (IVDs) are widely used in the field of AC measurements, such as impedance measurements at audio frequencies. Two-stage guarded IVD has been developed by D N. Homan and T L. Zapf about forty years ago. However, it is not easy to construct the two-stage guarded IVD. Therefore, we have developed a two-stage IVD using special winding method without guard by magnetic and electrical shield. To reduce admittances of each winding wires, corrugated cardboard of polypropylene is used for new two-stage IVD. In addition, ratio winding and excitation winding were wound toroidally around two FINEMET ring cores using PEW flat cable 0.7 mm in diameter. As a result, the in-phase ratio errors are within ±6.1×10-8 of the input at frequency 1kHz or less. In this report, the winding methods and measurement results of new two-stage IVD are described.
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  • Measurement Method of Vector Magnetic Properties of a Non-oriented Electrical Steel Sheet under Stress Conditions
    Yuichiro Kai, Yuji Tsuchida, Takashi Todaka, Masato Enokizono
    2012 Volume 132 Issue 10 Pages 930-935
    Published: October 01, 2012
    Released on J-STAGE: October 01, 2012
    DOIhttps://doi.org/10.1541/ieejfms.132.930
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    It is needed to know magnetic properties under various stress and magnetic flux conditions in order to utilize electrical steel sheets effectively. In this paper, we examine a measurement method of the vector magnetic properties of a non-oriented electrical steel sheet under stress conditions. At first, an evaluation method of the stress is examined in order to control the amplitude and direction of principal stress in the plane of the non-oriented electrical steel sheet. In addition, the vector magnetic properties of the non-oriented electrical steel sheet are measured by applying the stress along the arbitrary direction. As these results, the difference of the magnetic anisotropy of the non-oriented electrical steel sheet is obtained due to the stress.
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