N. Tsuya

Hosei University, Edo, Tōkyō, Japan

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Publications (23)31.14 Total impact

  • N. Tsuya · T. Tokushima · Y. Hirayama · Y. Oka
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    ABSTRACT: In a rigid disk a very smooth surface is desirable for high density recording, while it tends to stick to the magnetic head. To avoid this difficulty, the mechanical texturing (M/T) is widely used. Unfortunately very low flying height can’t be achieved with the M/T. To improve the flying height, authors have developed a new texturing process using anodically oxidized aluminum substrates named chemical texturing (C/T).<sup>1</sup> Aluminum anodic oxide films have a regularly arranged honeycomb structure and uniform and roughness‐controlled surfaces were formed by etching process of chemical texturing. In the present research, the relation between the recording and tribological properties and the etching conditions were investigated. On C/T substrates Cr, a longitudinal magnetic layer CoNi, C were sputtered in an inline sputtering equipment. The surface of the sputtered layer was flat (R a ≪5 Å) and uniform. Magnetic and electrical properties (coercive force, squareness, over write, modulation and so on) were examined. In spite of isotropy on the disk surfaces, the modulation caused by the inline sputtering was not observed, and high coercive force of 1200 Oe was obtained. Tribological properties (gride height, CSS, friction) were measured. Gride height was lower than 0.1 μm, and CSS more than 30 000 cycles. In semi‐pilot plant production, thousands of C/T disks were prepared. Yield of disks having less than 5 missing and/or extra pulses was higher than 95%.
    Journal of Applied Physics 05/1991; 69(8-69):5765 - 5765. DOI:10.1063/1.347866 · 2.19 Impact Factor
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    ABSTRACT: A digitizer with a cordless cursor to input coordinates of graphics is described. The digitizer utilizes magnetostrictive delay lines made of iron-base amorphous ribbons. During propagation of the magnetoelastic wave in the ribbon, the output signal is generated by a solenoid coil wound through the entire ribbon length when the wave arrives at a position immediately underneath the cursor magnet. Resolution of the above position was 0.1 mm, and a high cursor position of 12 mm was realized
    IEEE Transactions on Magnetics 06/1989; DOI:10.1109/20.24517 · 1.21 Impact Factor
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    ABSTRACT: Magnetic alumite disks were fabricated using an anodic oxidation method. An additional chemical texture process was effective in improving tribological properties. The recording characteristics of 10-, 20-, and 30-nm-textured disks were evaluated. A recording density of 50 kb/in was attained at 5 MHz and 5 m/s relative speed. Environmental tests were carried out, with excellent results
    IEEE Transactions on Magnetics 12/1988; 24(6-24):2661 - 2663. DOI:10.1109/20.92205 · 1.21 Impact Factor
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    ABSTRACT: Magnetic alumite discs were obtained using anodic oxidation method. An additional chemical texture process was effective in improving tribological and magnetic recording characteristics. These discs were confirmed to exhibit a large Kerr rotation as well as a refractance with an angle as large as one degree.
    Le Journal de Physique Colloques 12/1988; DOI:10.1051/jphyscol:19888886
  • A. Murakami · K. Hosaka · M. Fukushima · N. Tsuya
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    ABSTRACT: A digitizer was developed based on the operating principle of electromagnetic induction phenomenon and using high permeability amorphous wires as magnetic cores. The cordless advantage was realized by using a permanent magnet in the stylus pen. A high working height and high resolution of the stylus pen were achieved.
    Journal of Applied Physics 12/1988; 64(10-64):6062 - 6064. DOI:10.1063/1.342123 · 2.19 Impact Factor
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    H Nakamura · N. Tsuya · Y Saito · Y Katsumata · Y Harada
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    ABSTRACT: Quick quenching of high-silicon iron electric sheet with a third element, suppressed the formation of B2 superlattice. Using the single crystals, we found a dramatic decrease of room temperature anisotropy by lowering the degree of order. A statistical consideration describes the decrease of ordering temperature satisfactorily.
    Le Journal de Physique Colloques 11/1988; 49(C-8). DOI:10.1051/jphyscol:1988853
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    ABSTRACT: Concerning the decrease of the wall motion resistive magnetic properties such as magnetocrystalline anisotropy of an electric sheet, we reported that quick quenching from 1100 °C suppressed the formation of a B2 superlattice which is roughly proportional to the anisotropy. Using iron single crystals containing 5.5 wt. % silicon with the addition of a small amount of a third element such as Mo to suppress the formation of the superlattice, we describe the quenching temperature dependence of the anisotropy and saturation magnetization. A remarkable decrease of room‐temperature anisotropy was found in crystals with the additional element compared to those without the element.
    Journal of Applied Physics 11/1988; 64(10). DOI:10.1063/1.342273 · 2.19 Impact Factor
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    Y. Saito · Y. Kishino · K. Fukushima · S. Hayano · N. Tsuya
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    ABSTRACT: A Chua‐type magnetization model is derived by means of a Fourier series while the magnetic flux density is sinusoidally varying with time. It is shown that this Chua‐type model is well suited for practical computations of magnetodynamic field. A geometrical duality between the Delaunay triangles and associated Voronoi polygons is utilized to implement a dual energy finite element approach. As an example, the magnetodynamic fields in a toroidal reactor including the effects of transients, eddy currents, and hysteresis are computed.
    Journal of Applied Physics 05/1988; 63(8-63):3174 - 3178. DOI:10.1063/1.340830 · 2.19 Impact Factor
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    ABSTRACT: Flexible alumite discs were prepared and their recording characteristics and wear resistance is reported. To study the surface roughness of alumite film, single-crystal Al platelets with different crystallographic orientations were prepared and anodic oxidized. The surface smoothness of these anodized films was better in the order [111]>[110]>[100]. For a flexible-disc substrate, >99.999%-pure Al was sputtered onto 50- mu m-thick PET film at a substrate temperature of 80 degrees C. The sputtered film was oriented favorably with [111]. After Fe was electrodeposited in the pores of 2- mu m-thick anodized Al film, it was polished to a thickness of 1 mu m. To test wear durability, the surface of the alumite layer was slightly etched and applied with liquid lubricant. A recording density D<sub>50</sub> of 60 kB/in. was obtained, together with a wear resistance of five million head passes.
    IEEE Transactions on Magnetics 04/1988; 24(2-24):1790 - 1792. DOI:10.1109/20.11603 · 1.21 Impact Factor
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    ABSTRACT: A digitizer with a cordless cursor to input the coordinates of graphics is reported. The digitizer utilizes magnetostrictive delay lines made of iron-based amorphous ribbons. During the propagation of a magnetoelastic wave ion the ribbon, the output signal is generated by a solenoid coil wound through the entire ribbon length when the wave arrives at a position immediately underneath the cursor magnet. The resolution of the digitizer is +or-0.1 mm; the cursor position was still detectable even when placed 12 mm above the pad surface.
    IEEE Transactions on Magnetics 04/1988; 24(2-24):1758 - 1760. DOI:10.1109/20.11593 · 1.21 Impact Factor
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    Y. Saito · K. Fukushima · S. Hayano · N. Tsuya
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    ABSTRACT: Previously, we have proposed a specific Chua type model, and shown that our model is closely related with the Preisach and Rayleigh models. In the present paper, a simple linearized Chua type model is proposed for the loss and skin effect calculations. As a result, it is found that the hysteresis makes the skin depth deeper.
    IEEE Transactions on Magnetics 10/1987; 23(5-23):2227 - 2229. DOI:10.1109/TMAG.1987.1065663 · 1.21 Impact Factor
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    ABSTRACT: Details are given of a method of measuring perpendicular magnetic alumite discs using anodization with an additional new process called "pore widening" which is effective in controlling the coercive force. Electro-deposited fine iron needles were in a single crystalline state, and the perpendicular orientation of magnetization was confirmed. The resulting magnetic recording characteristics of the rigid discs were satisfactory, indicating usefulness of the method as a perpendicular recording medium.
    IEEE Transactions on Magnetics 10/1987; 23(5-23):2242 - 2244. DOI:10.1109/TMAG.1987.1065643 · 1.21 Impact Factor
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    ABSTRACT: Details of making are given of perpendicular magnetic alumite, discs obtained by an aid of anodization with the additional new process named "pore widening" which was effective to control the coercive force. The electrodeposited fine iron needles were in single crystalline state. The perpendicular orientation of magnetization was confirmed. The magnetic recording, characteristics of rigid discs indicated a hilgh potential for use as a perpendicular recording medium.
    IEEE Transactions on Magnetics 02/1987; 23(1-23):53 - 55. DOI:10.1109/TMAG.1987.1064805 · 1.21 Impact Factor
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    ABSTRACT: A chua type magnetization model is presented and closely examined to the other models. As a result, it is revealed that a Chua type model is closely related with the Preisach type model and gives the Rayleigh relationships in the weakly magnetized region. Moreover it is shown that the magnetization processes are essentially accompanying the magnetic aftereffects.
    IEEE Transactions on Magnetics 10/1986; 22(5-22):647 - 649. DOI:10.1109/TMAG.1986.1064567 · 1.21 Impact Factor
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    ABSTRACT: Perpendicular magnetic alumite discs were obtained using an anodic oxidation method.The additional new pore widening process was effective to control the coercive force. The electro-deposited fine iron needles were single crystals and the growth direction was [110]. The recording characteristics of 3.5 and 5.25 inch rigid discs were evaluated. A recording density D 50 of 50 KBPI was attained for the disc with a media thickness 1.5 µm. The environmental test under an atmosphere of of 40 °C 90 % R. H. over 1000 hr affirmed the stability of the alumite disc with 250A SiO 2 overcoat.
    IEEE Transactions on Magnetics 10/1986; 22(5-22):1140 - 1145. DOI:10.1109/TMAG.1986.1064316 · 1.21 Impact Factor
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    ABSTRACT: Because of their simplicity and flexibility, first order triangular finite elements are the most widely used type of finite element in magnetic field computation. However, in the first order finite element procedure, a relatively large number of mesh points is required to obtain good solutions. In order to overcome this difficulty, we propose a new method of magnetic field computation based on locally orthogonal discretizations. Memory requirements and solution times are dramatically reduced by the new method.
    IEEE Transactions on Magnetics 10/1986; 22(5-22):1057 - 1059. DOI:10.1109/TMAG.1986.1064432 · 1.21 Impact Factor
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    ABSTRACT: Magnetic properties of electrodeposited alumite media for perpendicular recording were investigated. By means of the pore widening process enabled to realize the coercive force less than 1000 Oe. Mössbauer spectra suggested that the direction of magnetization of the processed alumite was almost perpendicular to the surface.
    Journal of Magnetism and Magnetic Materials 02/1986; 54-57:1681-1682. DOI:10.1016/0304-8853(86)90975-3 · 2.00 Impact Factor
  • Y. Saito · S. Hayano · H. Nakamura · Y. Kishino · N. Tsuya
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    ABSTRACT: The magnetization characteristics are separated into the saturation and hysteretic properties by the Fourier series while the induction is sinusoidally varying with time. These two properties yield the parameters of a Chua type model, which is closely related with the Preisach type models.
    Journal of Magnetism and Magnetic Materials 02/1986; 54:1613-1614. DOI:10.1016/0304-8853(86)90947-9 · 2.00 Impact Factor
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    Y. Saito · S. Hayano · N. Tsuya
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    ABSTRACT: The method of magnetic circuits has been proposed for evaluating the 3-D magnetodynamic fields in electromagnetic devices [1-3]. In this paper, we elucidate that our previous magnetic circuit method is one of the complementary network methods. Since the complementary network method is fundamentally based on the geometrical dual property associated with the element discretizations, it is found that this method is quite useful to give a circuit interpretation of field computations [4]. As an illustrative example, the dynamic fields in a toroidal reactor are computed by the complementary network method.
    IEEE Transactions on Magnetics 12/1985; 21(6-21):2280 - 2283. DOI:10.1109/TMAG.1985.1064234 · 1.21 Impact Factor
  • M. Shiraki · Y. Wakui · T. Tokushima · N. Tsuya
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    ABSTRACT: Magnetic alumite films containing electrodeposited Ni, Co and Fe were successfully prepared by employing an additional new process in the conventional anodic oxidation method in order to obtain suitable perpendicular coersive force below 1000 Oe. By this new process, the diameter of the micropores in the oxide layer was widened above 400 Å. The recording characteristics of the 5.25 inch rigid disks were evaluated using a Mn-Zn ferrite ring head with a gap length of 0.5μm. A recording density D50 of 42 kBPI was obtained for the disk with a media thickness of 1.5μm and a coercivity of 950 Oe. The output voltage was 1.2μ Vpp / μm. turn at 20 kBPI. Higher recording density of D50 was expected for the disk with a media thickness below 1.5 μm. It was shown that the present medium exhibit higher potential for recording than a conventional plated medium at high recording density region.
    IEEE Transactions on Magnetics 10/1985; 21(5-21):1465 - 1467. DOI:10.1109/TMAG.1985.1064078 · 1.21 Impact Factor