IEEJ Transactions on Fundamentals and Materials
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
Volume 115, Issue 10
Displaying 1-21 of 21 articles from this issue
  • Kaneo Mohri
    1995 Volume 115 Issue 10 Pages 927-929
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
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  • Koichiro Inomata, Yoshiaki Saito, Sigeo Honda, Masahiko Nawate
    1995 Volume 115 Issue 10 Pages 930-935
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    The correlation between giant magnetorisitance (GMR) and interface structure were investigated in Co/Cu and Co/Cu/NiFe/Cu multilayers as well as model calculation. The calculation revealed that interfacial ferromagnetic coupling reduces MR ratio and induces triangular-like shape MR curves. 59Co NMR measurement in zero field in a Co/Cu multilayer indicated that the temperature dependence of the interface Co hyperfine field is larger than that of the bulk Co hyperfine field, which correlates with the temperature dependence of GMR in the Co/Cu. This suggests that the GMR originates from the spin-dependent interface scattering. The correlation between interface structure and GMR was also demonstrated for Co/Cu/NiFe/Cu multilayers with non-interlayer coupling, which implies that the interface structure intrinsically affects GMR, independent of the interlayer coupling.
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  • Hiroyuki Wakiwaka, Tatsuo Nakayama, Takayuki Hirano, Yoshiaki Nagasawa ...
    1995 Volume 115 Issue 10 Pages 936-942
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    A magnetic anisotropy sensor (MAS) is a probe-type sensor capable of non-contact, non-destructive measurement of stress in ferromagnetic materials. The output voltage of the MAS is induced by a directional difference of relative permeabilities caused by the inverse magnetostrictive effect.
    It is often necessary that the internal stress distribution in the direction of depth should be clarified. By changing the MAS exciting frequency, it is possible to searching for the different depth stress. This paper proposes a method for measuring the stress distribution in the direction of depth. Furthermore, this paper shows that the stress distributions in the measurement surface and opposing surface can be estimated from the MAS output.
    In this paper we discuss the followings:
    (1) By developing a stress-electric conversion theory of the MAS, it is clarified that the output voltage is proportional to the principal stress differences.
    (2) Using punched thin steel sheet as a specimen, by changing the exciting frequency, the measurements from one side makes it possible to estimate the stress in the opposite surface.
    (3) Conversion of the principal stress differences to relative permeabilities reveals that tensile stress remains in the upper surface, and compressive stress exists in the lower surface.
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  • Ken-ichi Bushida, Tsuyoshi Uchiyama, Kaneo Mohri
    1995 Volume 115 Issue 10 Pages 943-947
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    A new sensitive micro-sized single head field sensor using Colpitts oscillator with a negative feedback loop is constructed based on the Magneto-Impedance (MI) effect using a slightly negative magnetostrictive amorphous wire (Fe4.35 Co68.15 Si12.5B15, 30μm dia., 1-3mm length, 2kg/mm2 tension annealed), The MI element is used as an inductive element in the Colpitts oscillator, and is magnetized with a resonant circuit ac current (70MHz) biased with a DC current. A DC bias field Hb and a feedback field Hf are generated by the coil current around the MI element for realizing an asymmetrical MI characteristic regarding the sign of an external field Hex. An accurate linear relation of the sensor output voltage (Eout) versus Hex characteristics was obtained.
    This paper reports the principles and basic properties of the sensor. Applications to a rotary encoder head for a ring magnet of 19mm dia. having 1, 000 poles, and a direction sensor utilizing the terrestrial magnetic field are also shown.
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  • Tsuyoshi Uchiyama, Kaneo Mohri, L. V. Panina, Kazuhide Furuno
    1995 Volume 115 Issue 10 Pages 949-955
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    The CoFeB zero-magnetostrictive amorphous film samples for investigation of the magnetoimpedance (MI) effect were prepared by RF sputtering. The film was etched to form a strip pattern having 1-4μmthickness, 300mu;m width and 10mm length. The relation between annealing conditions and MI characteristics was investigated for those films. Impedance Z monotonically decreases with increasing applied field Hex when a high frequency sinusoidal current was applied to the sample annealed in a rotating field. In case of the sample having transverse anisotropy, Z sharply increases with Hex for the region Hex<Hk (anisotropy field). MI ratio (ΔZ/Z0/Oe) of 8%/Oe was obtained for the sample which was annealed in the DC field (or applying DC current) after annealing in the rotating field.
    The colpitts oscillator type field sensor was constructed using the film element. The amplitude of oscillation voltage Ef is 0.13V at Hex=0 and increased to 0.44V at Hex=10Oe. The changing ratio ΔEf/Efo is 240% at 10Oe (24%/Oe) which is more than three times greater than MI ratio, because a current amplitude If also increases with Hex in the resonance circuit. A direction sensing utilizing the terrestrial field was carried out using the MI-colpitts sensor.
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  • Y. Saito, T. Kamezawa, Y. Hirama
    1995 Volume 115 Issue 10 Pages 956-961
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    This paper proposes a three phase magnetic sensing system which makes it possible to detect the defect, bending and deflection of metallic plate. Operating principle of this system is based on the essential nature of three phase transformer circuit. When balanced three phase currents are fed into the primary coils which work as the sensing part, zero phase voltage is detected if the target, i. e. secondary circuits. has defects. Zero phase voltage is not detected if the target' has no defects. Experimental verification was carried out about the defect, bending and deflection of the metallic plates.
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  • Kyoshiro Seki, Hiroshi Osada, Koichi Murakami
    1995 Volume 115 Issue 10 Pages 962-967
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    The magnetic semiconductor sensor MSS utilizing the magnetic and electrical properties of ferrimagnetic substance having various possible Curie temperatures shows similar characteristics in a temperature-sensitive magnetic core, a thermistor and a varistor. When applying plural signals to MSS, it discriminates automatically to magnetic and electrical outputs without mutual influence, so that a magnetic/electrical sensor with a single MSS is constructed. The temperature dependence, magnetic distortion and pyromagnetic MSS's magnetic property can be applied for temperature, pressure, supersonic and photo sensors. The electrical characteristic responds to humidity, gas and taste, further indicates the switching function at high voltage range. Thus, multi-ability MSS can be used as a combination sensor in the field of environmental monitor, remote sensing, artificial sensory device, photomagnetic conversion, biotechnology and power electronics. The basic characteristics and application for multisensor module and photo sensor of MSS is discussed here.
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  • Hiroshi Yamakawa, Noboru Ishikawa, Kazuo Chinone, Satoshi Nakayama, Ak ...
    1995 Volume 115 Issue 10 Pages 968-973
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    We investigated the new nondestructive evaluation techniques for construction based on measuring the magnetic field. For one of the applications of these techniques, we estimated the position of a steel bar in concrete by using a SQUID sensor. We obtained the way to abstract a component of the magnetic field from a magnetic model of a steel bar with regard to the symmetry. This made it possible to estimate the position of a steel bar without necessity of magnetizing it artificially. A planer typed first order SQUID gradiometer was used, since it is a well balanced thin film gradiometer, and it is not readily affected by environmental magnetic noises.
    We tested this procedure by running an experiment using specimens. The results showed that the horizontal position is able to be estimated within 1 millimeter. On the other hand, the estimation of depth may be realized by using the regression equation.
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  • Kohichi Ogata, Yorinobu Sonoda
    1995 Volume 115 Issue 10 Pages 974-979
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    This paper introduces a useful articulatory measuring system using magnetometer sensors for monitoring tongue point movements during speech production. The system consists of small permanent magnetic rods which are attached to the tongue surface as pellets, and magnetometer sensors having two amorphous alloy cores. A measuring principle is based on a change in the intensity of the fields related to distances between the magnetic rods and sensors.
    On the detection of rods' positions, tilting and lateral movements of the rods on the tongue cause measurement errors and such troublesome movements are serious problems in the magnetic sensing system using similar principle. These errors can be effectively reduced by setting four sensors at each side of the jaw where the sensors detect positions and inclination angles of the rod. Experiments were done on one point of the tongue surface by using this method, and characteristic patterns of the tongue articulatory movements were observed on several test words.
    Moreover, experimental results obtained from a newly developed method of detecting positions and inclination angles of two rods are also shown in the paper.
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  • Takafumi Iwamoto, Jiro Yamasaki
    1995 Volume 115 Issue 10 Pages 980-985
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Compositional dependence of magnetoresistance were investigated for (Fe, Co, Ni)-Cu melt-spun granular ribbons. It was found that the (Co75Ni25) 20 Cu 80 and (Fe22.35Ni77.65) 30Cu 70 ribbons annealed at 500°C for 30min. exhibits giant magnetoresistance (GMR) ratio of about 18 and 16%, respectively. For the Fe-Ni-Cu ribbons exhibiting large GMR, the magnetic particles were taken out of Cu matrix by chemical etching and change of magnetic property was studied. It was found that there is anti-ferromagnetic coupling between the magnetic particle in the Cu matrix as in multi-layered films.
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  • Tadayuki Nakano, Jiro Yamasaki
    1995 Volume 115 Issue 10 Pages 986-992
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Non-magnetostrictive Fe-Co-Si-B amorphous ribbons annealed in a demagnetized state exhibits magnetization reversal with large Bazkhausen discontinuities due to domain wall pinning caused by the locally induced anisotropy. To increase the stability of the large Barkhausen discontinuities, domain walls, domain patterns and magnetization reversal process of wall pinned amorphous ribbons were studied in detail using a Kerr microscope.
    It was found that the domain wall width and its pinning field were increased markedly by annealing and that the large Barkhausen discontinuities caused by depinning of one of walls of multiple closure domains existing near the ribbon ends due to demagnetizing field. It was also found that the instability of the large Barkhausen discontinuities is related to the dispersion of depinning field of walls of multiple closure domains.
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  • Toru Inaguma, Hiroaki Sakamoto
    1995 Volume 115 Issue 10 Pages 993-998
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    A Magnetic Head with high S/N ratio, for detecting Barkhausen Noise (BHN) of ferromagnetic steels, has been developed. This magnetic head has two characteristics. Namely, the BHN signals can be detected under conditions of (a) the induction search coil being lifted off from the surface of the steel at a distance of as large as 4mm, and (b) without using a frequency filtering device which is required in a conventional method. We analyzed the performance of the magnetic head on the basis of the magnetic flux density distribution around the search coil.
    This magnetic head can be applied for evaluating microstructures, stress and mechanical properties of the steels nondestructively not only in a steel manufacturing process but also in a paint coating and/or rusty conditions.
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  • Noriya Ebine, Shinjiro Takeuchi, Katsuyuki Ara
    1995 Volume 115 Issue 10 Pages 999-1006
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    Bobbin-coil-type eddy current probes, which are conventionally used for nondestructive inspection of steam generator tubes in pressurized-water-type nuclear power plants, have poor detectability for circumferential flaws. Hence a new type of eddy current probe was proposed to detect effectively the magnetic flux component disturbed by a flaw and thus to eliminate the flaw direction dependency on the flaw detectability. In the course of development of the proposed method, structures of the probe were investigated based on the measurement of magnetic fields induced by exciting flat coils with several shapes. The new type of probe proposed here consists of differential pick-up coils detecting magnetic flux and exciting coils having a parallelogrammic shape, and its structure was fabricated experimentally in order to detect flaws independently of their directions. Nondestructive flaw detection tests was then conducted by using the probe. The results obtained showed clear evidences that both the horizontal and the vertical slitflaws and even the small hole of 0.5mm in diameter can be detected successfully.
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  • Hironori Matsuba
    1995 Volume 115 Issue 10 Pages 1007-1012
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    Magnetic field penetration through a superconductive wall is expressed in general cases including the wall thickness close to the London penetration depth of the superconductor. In addition, solutions of the field penetration for a superconducting cylinder of infinite length and for a superconducting spherical shell are given. Using the solution, magnetic field penetration through a very thin superconducting film is discussed compared with the conventional solutions.
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  • Yuji Nishibe, Yutaka Nonomura, Koji Tsukada, Masaharu Takeuchi
    1995 Volume 115 Issue 10 Pages 1013-1021
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    A magnetic head type torque sensor has the following advantages; easiness of incorporation, noncontact detection, high sensitivity, small size and light weight. On the other hand, two major issues to be considered on this type of sensor are the strong dependence of the sensor output on variation of gap between the sensor head and a torque transmitting shaft due to its off-center motion, and the fluctuation of the sensor output around a circumference of the shaft due to heterogeneousness of magnetic properties on the shaft surface.
    Two issues described above, have been overcome by means of the correction of the sensor output at each detecting position using the correction coefficients of the sensor sensitivity and the offset output, and the multi-arrangement of sensor heads around the shaft, respectively. Furthermore, it is shown that the dependence of sensor output on temperature is reduced to one seventh in comparison with a conventional single-head type sensor and this sensor is useful for measurement of combustion torque generated by automobile engine.
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  • Yoshihiro Tani, Hideo Ikada, Masashi Okabe, Masaharu Moriyasu, Katsuyu ...
    1995 Volume 115 Issue 10 Pages 1022-1027
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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    Formation of magnetic gratings on steel plate by electron-beam and laser beam irradiation has been studied. Ferromagnetic carbon steels, ferromagnetic stainless steels and nonmagnetic austenitic stainless steels were used for the test samples. The gratings were magnetized in a D. C. magnetic field, and the profile of the leakage magnetic flux on the steel plate was measured. The changes of microstructure and mechanical hardness of the beam-irradiated portions were also investigated. The leakage flux profiles show the existence of remanent magnetization in the gratings. The steel with the gratings can be applied as a material of the magnetic scale at 300&deg;C.
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  • Masashi Sato
    1995 Volume 115 Issue 10 Pages 1028-1029
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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  • Mitsuyasu YATSUZUKA, Tohru YAMASAKI, Yoshiyuki HASHIMOTO, Hitoshi UCHI ...
    1995 Volume 115 Issue 10 Pages 1030-1031
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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  • Ken Mochizuki, Takao Miyashita
    1995 Volume 115 Issue 10 Pages 1032-1033
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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  • Ryuichi Miyano, Shinya Izumi, Ryouji Kitada, Motoyuki Fujii, Shunjiro ...
    1995 Volume 115 Issue 10 Pages 1034-1035
    Published: September 20, 1995
    Released on J-STAGE: July 15, 2008
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  • 1995 Volume 115 Issue 10 Pages 1042
    Published: 1995
    Released on J-STAGE: December 26, 2008
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