ZIB

1

Digitale Medien

Dependence of magnetic properties of Co-Pt films on sputtering conditions (1985)

Hoshi, Y. ; Matsuoka, M. ; Naoe, M.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 57 (1985), S. 4022-4024

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ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Magnetic properties, Young's modulus, and corrosion resistance of Co-Pt films deposited by targets-facing type of sputtering (TFTS) have been investigated. The films deposited at a Ar gas pressure PAr of 2 mTorr present good surface smoothness and dense texture. The c axis of the hexagonal crystallites in the film orients normal to the film plane. The films have nearly the same value of Young's modulus (≈17×1011 dyn/cm2) as that of the bulk Co-Pt alloy. On the other hand, the films deposited at PAr of 30 mTorr exhibit rough surface and columnar structure and do not exhibit any preferred orientation of crystallites. In addition, they have a small value of Young's modulus (≈5×1011 dyn/cm2) and poor corrosion resistance compared with the film deposited at low PAr. They have coercive force Hc larger than 1 kOe, which is mainly caused by their porous structure. Besides, the Co-Pt films have large in-plane uniaxial magnetic anisotropy, which is caused by both dc magnetic field applied to substrate during deposition and oblique incidence of sputtered particles upon substrate.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.334658

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2

Digitale Medien

Effect of additional element (Fe, Zr, Ta) for Co-Cr films deposited by targets facing type of sputtering (1985)

Naoe, M. ; Matsuoka, M. ; Hoshi, Y.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 57 (1985), S. 4019-4021

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ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: In order to improve both magnetic properties and wear resistance of Co-Cr films for perpendicular magnetic recording media, the effect of the addition of a small amount of Fe, Zr, and Ta to the Co-Cr binary alloy films has been investigated. They were deposited with a targets facing type sputtering (TFTS) apparatus. (i) The addition of a small amount of Fe (〈5 at. %) causes a significant decrease of the effective perpendicular magnetic anisotropy K⊥ (K⊥=Ku−2πM2s). The K⊥ has a negative value at Fe content above 1 at. %. Consequently, the recording characteristics become worse as Fe content increases. (ii) The addition of Zr leads to a remarkable decrease of grain size and improvement of surface smoothness along with an increase of wear resistance. It also causes evident decrease in Ku and saturation magnetization Ms. However, both K⊥ and remanence ratio Mr⊥/Mr(parallel) are increased by the addition of a small amount of Zr up to 0.5 at. %, though they decrease steeply with further increase of Zr content above 1 at. %. (iii) The addition of Ta shows almost the same tendency as Zr for the film structure and wear resistance. It also causes the decrease of Ku. But the K⊥ increases with an increase of Ta content up to 0.5 at. % and takes nearly constant value at Ta content above 0.5 at. %, since the Ms of the film decreases remarkably as Ta content increases. Mr⊥/Mr(parallel) increases gradually from 2.5 to 3.6 as Ta content increases. Consequently, the addition of a small amount of Ta is effective for improving both recording characteristics and wear resistance.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.334657

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3

Digitale Medien

Ba–ferrite thin-film disk for perpendicular magnetic recording (1985)

Matsuoka, M. ; Naoe, M. ; Hoshi, Y.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 57 (1985), S. 4040-4042

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ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: The authors have prepared Ba–ferrite film disks and evaluated their magnetic read/write characteristics. The c-axis-oriented Ba–ferrite thin films were formed epitaxially on c-axis-oriented ZnO films by means of a targets-facing-type sputtering system. The direction of easy magnetization in the film with perpendicular crystalline anisotropy is almost perpendicular to the film plane. Thus, the perpendicular remanence is more than 60 times as large as the in-plane one. The simple Ba–ferrite films, however, have a coercive force, Hc⊥ above 2 kOe which is too large to write on by means of a conventional head. The substitution of In3+ in the Ba–ferrite films makes the Hc⊥ values decrease to about 1 kOe without increasing the critical temperature, Tcritical, of c-axis orientation. The read/write characteristics of the films were measured with a MnZn–ferrite ring head. The reproduced signal exhibits clear dipulsive waveforms as the dipulse ratio exceeds 0.7. Furthermore, the overwrite ratio decreases below −28 dB for the In3+-substituted Ba-ferrite film disk. The Ba–ferrite film disks have promising potential as a high-density perpendicular magnetic recording medium.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.334664

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4

Digitale Medien

Discovery of an unusual hard X-ray source in the region of supernova 1987A (1987)

Dotani, T. ; Hayashida, K. ; Inoue, H. ; [weitere]

[s.l.] : Nature Publishing Group

Nature 330 (1987), S. 230-231

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ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] We have been regularly observing SN1987A from the X-ray astronomy satellite Ginga1'2 since 25 February 1987, immediately following the optical discovery2'3. Ginga carries a set of proportional counters of 4,000 cm2 effective area and a field of view of 2°x4° full width. SN1987A (hereafter ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/330230a0

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5

Digitale Medien

In vitro analysis of lymphocyte functions in common variable immunodeficiency: heterogeneity in B-cell defects (1986)

Matsuoka, H. ; Okada, J. ; Takahashi, T. ; [weitere]

Springer

European journal of pediatrics 145 (1986), S. 252-257

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ISSN: 1432-1076

Schlagwort(e): Common variable immunodeficiency ; T, B co-culture ; B-cell defect

Quelle: Springer Online Journal Archives 1860-2000

Thema: Medizin

Notizen: Abstract Ten patients with common variable immunodeficiency were classified into three groups according to the number of circulating B-cells, i.e. B-cells being absent (three patients), very low (three patients) or within the normal range (four patients). The four patients in the last group showed significant proliferative responses to the T-independent B-cell mitogen, formalin-fixed Staphylococcus aureus, Cowan I. Further study of these patients by co-cultures with allogeneic T or B-cells in various combinations with pokeweed mitogen showed that two patients had an intrinsic B-cell defect without T-cell defect. The third patient had a T-cell dysfunction (i.e. his T-cell could only help the B-cells of some individuals) resulting in a defect in Ig production. The T-cells of the fourth patient showed poor helper function towards all controls. All six patients with absent or very low numbers of B-cells in group I and II had normal T-cell helper function. This study demonstrates that the immunological defect in common variable immunodeficiency is most often a B-cell defect at different stages of their differentiation with sometimes an additional T-cell dysfunction.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00439395

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6

Digitale Medien

Coordinated optical-EXOSAT-tenma observations of a burst from 2S1636-536 (1985)

Turner, M J L ; Breedon, L M ; Ohashi, T ; [weitere]

Springer

Space science reviews 40 (1985), S. 249-253

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ISSN: 1572-9672

Quelle: Springer Online Journal Archives 1860-2000

Thema: Physik

Notizen: Abstract During a coordinated observations of 2S1636-536 with EXOSAT, Tenma and the 1.4 metre Danish telescope at La Silla, a single burst was detected at all three observatories. The burst was bright with a peak flux of 6 × 10-8 ergs/cm 2 /s and rapid expansion of the blackbody radius. EXOSAT and Tenma agree closely in the values of blackbody radius, temperature and flux which are very similar to the three bursts recently reported by Tenma which appear to reach the Eddington flux limit at their peak. Preliminary analysis of the X-ray and optical timing data reveal that this burst is unusual in having a sharp leading edge in both X-ray and optical data and a very short X-ray-optical delay compared with those previously observed. If confirmed, this result puts significant restraints on the location of the optical reprocessing site.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00212894

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