Hitachi, Ltd.

Hitachi Maxell, Limited

Norikazu Tsumita

Yoshihiro Shiroishi

Hiroyuki Suzuki

Masaki Ohura

Sadao Hishiyama

Yoshibumi Matsuda

Kazumasa Takagi

Tomoyuki Ohno

Yotsuo Yahisa

Takaaki Shirakura

Noriyuki Shige

Yutaka Sugita

Hiroshi Umezaki

Masaaki Hayashi

Kazuetsu Yoshida

Takeo Yamashita

Sadanori Nagaike

Hirozi Yamada

Hideki Nishida

Yasushi Kitazaki

Yoshio Gobara

Hideaki Tanaka

Tadashi Ikeda

Makoto Saito

Masaaki Futamoto

Noriyuki Kumasaka

Yukio Honda

Katsuhiro Kuroda

Naoki Koyama

Kazuo Shiiki

Yoshiki Kato

Makoto Sano

Kenji Furusawa

Toshio Niihara

Tsuneo Suganuma

Noriaki Okamoto

Katsuo Abe

Yoshihiko Miyake

Tokuho Takagaki

Hiroyuki Kataoka

Nagatugu Koiso

Kenichi Gomi

Seiichi Asada

Nobuo Nakagawa

Youji Maruyama

Toyoji Okuwaki

Katsuhiro Kaneko

Shoichi Sawahata

Shinichiro Saitoh

Suzuki Hiroyuki

Katuo Uda

Maki Kondo

A magnetic recording medium for longitudinal recording with a low media noise, a high S/N ratio and high reliabilities in corrosion resistance is disclosed. By making a magnetic layer from a Co-based alloy comprising 1 to 35 at. % of at least one element selected from the group consisting of Pt and Ir, 1 to 17 at. % of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ge and Si, except for Si, whose concentration is 1 to 40 at. and 0.1 to 10 at. of oxygen, a magnetic recording medium for longitudinal recording having an inplane coercivity of 1,200 Oe or more and a coercive squares of not more than 0.85 is obtained. A process for producing the magnetic recording medium for longitudinal medium and a magnetic memory apparatus using the magnetic recording medium for longitudinal recording are also disclosed.

Magnetic recording media for longitudinal recording, process for producing the same and magnetic memory apparatus

A magnetic recording medium including a substrate and a magnetic layer on the substrate which is a Co-based alloy including Pt and/or Ir, including at least one of Ti, Zr, Hr, V, Nb, Ta, Cr, Mo, W, Ge, and Si, and including oxygen. A magnetic memory apparatus including the magnetic recording medium.

Magnetic recording media for longitudinal recording

A magnetic recording medium for longitudinal recording with a low media noise, a high S/N ratio and high reliabilities in corrosion resistance is disclosed. By making a magnetic layer from a Co-based alloy comprising 1 to 35 at. % of at least one element selected from the group consisting of Pt and Ir, 1 to 17 at. % of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ge and Si, except for Si, whose concentration is 1 to 40 at. %, and 0.1 to 10 at. % of oxygen, a magnetic recording medium for longitudinal recording having an inplane coercivity of 1,200 Oe or more and a coercive squares of not more than 0.85 is obtained.

There is provided a magnetic disk apparatus including at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate; a magnetic head which faces the magnetic disk in a rotating state with a micro gap and is supported by a slider; rotating means for rotating the magnetic disk; and magnetic head positioning means for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein a plurality of protrusions each having a flat surface are formed in at least a region on the surface of the magnetic disk where a contact start/stop operation can be executed, an area ratio of the protrusions per 1 mm.sup.2 lies within a range from 0.1 to 80%, a height of the protrusion of the maximum height among the protrusions lies within a range from 5 to 40 nm, and the magnetic layer is formed on the whole surface on the base plate. According to the above magnetic disk apparatus, the frictional force between the disk and the head is small, and the floating height of the head can be reduced, and good floating stability is obtained, so that excellent recording and reproducing characteristics are obtained.

Magnetic disk with surface protective layer having convex portions and

A magnetic recording medium that uses, as a protective coating layer provided on a magnetic layer for magnetically recording signals, a layer made of a nonmagnetic material consisting of two ore more elements of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, and one or more elements of N, C, O, and B, or made of a magnetic material consisting of one or more elements of Co, Fe, Ni, and Gd, one or more elements of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, and one or more elements of N, C, O, B, and Si is excellent in sliding endurance. When the protective coating layer is made of the nonmagnetic material, the magnetic recording medium is also excellent in corrosion resistance, and when the protective coating layer is made of the magnetic material, the spacing between a magnetic head and the magnetic recording medium can advantageously be made large. Both the cases are high in reliability, and suitable for high density magnetic recording. The magnetic recording medium can be used in combination with a magnetic head that uses a metal magnetic alloy as at least part of the magnetic core to provide an excellent magnetic storage.

Magnetic recording medium and magnetic storage

Disclosed are longitudinal recording media comprising a composite magnetic film formed on a nonmagnetic substrate directly or through a nonmagnetic underlayer, in which all of magnetic thin films constituting the composite magnetic film are magnetically connected, the composite magnetic film has a single in-plane coercivity, and the in-plane coercivity is greater than the in-plane coercivity of a longitudinal magnetically anisotropic magnetic thin film constituting a magnetic thin film nearest to an information recording side among the magnetic thin films constituting the composite film.

Longitudinal magnetic recording media and magnetic memory units

A magnetic recording medium for longitudinal recording with a low media noise, a high S/N ratio and high reliabilities in corrosion resistance is disclosed. By making a magnetic layer from a Co-based alloy comprising 1 to 35 at. % of at least one element selected from the group consisting of Pt and Ir, 1 to 17 at. % of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W. Ge and Si, except for Si, whose concentration is 1 to 40 at. %, and 0.1 to 10 at. % of oxygen, a magnetic recording medium for longitudinal recording having an inplane coercivity of 1,200 Oe or more and a coercive squares of not more than 0.85 is obtained. A process for producing the magnetic recording medium for longitudinal medium and a magnetic memory apparatus using the magnetic recording medium for longitudinal recording are also disclosed.

Magnetic recording media for longitudinal recording, process for

The present invention relates to a magnetic recording medium for a magnetic disk unit or the like and, more particularly, to a magnetic recording medium having its recording layer made of a magnetic alloy film with uniform magnetic characteristics. The present magnetic recording medium comprises a non-magnetic substrate, at least two sputtered layers of chromium thin film having a bow-like columnar structure which chromium thin film is laminated on the substrate, another sputtered layer of a magnetic alloy thin film laminated on the chromium thin film, and a protective layer laminated on the magnetic alloy thin film. The present invention is effective in reducing modulation of regenerative output relatively independent of a texture roughness of the substrate.

Magnetic recording medium and method of producing same

Disclosed are a magnetic recording medium having a magnetic recording layer formed of a magnetic thin film in which rotational hysteresis integral R.sub.H is within a range of from 0.4 to 1.3 in the measurement by a torque magnetometer, and a continuous magnetic recording medium in which crystal grains are substantially randomly arranged on the upper surface of a magnetic recording layer or on the surface of a non-magnetic subbing layer, and in which each of the crystal grains is made to be in the form of an ellipsoid or needle and to have a length-ways axial ratio of a major axis to a minor axis not smaller than 2, more preferably, not smaller than 4.

Magnetic recording medium

A magnetic recording medium in which a non-magnetic intermediate layer made of an alloy substantially composed of at least one element selected from the group consisting of Zr, Hf, Ta, Ti and Nb is disposed between a magnetic layer formed on a substrate and a non-magnetic overcoat layer formed on the magnetic layer. Since the impact shock resistance and the vibration resistance of the magnetic recording medium can be improved and the head-medium spacing of the magnetic disc apparatus can be decreased extremely by disposing the non-magnetic intermediate layer, it can provide a increase in the recording density, particularly, in a thin film type magnetic recording medium using a metallic magnetic thin film or metal oxide thin film as the magnetic layer. It can also improve the corrosion resistance in the case of a metallic magnetic thin film type medium.

In a magnetic recording medium including an underlayer and a magnetic layer formed sequentially on a substrate, the underlayer is composed of a composite underlayer having an at least two-layered structure, the underlayer on the side of the substrate is made of a material providing low modulation to the magnetic recording medium while the underlayer on the side of the magnetic layer is made of a material providing a high S/N ratio to the medium. This makes it possible to obtain a magnetic recording medium having low modulation and high S/N ratio.

A magnetic recording medium comprises a non-magnetic substrate and a thin magnetic film, the thin magnetic film being composed mainly of Co, Ni and at least one of Zr and Hf, and a concentration of Zr, Hf or Zr and Hf as contained in the thin magnetic film being 0.1 to 30% by atom on the basis of the total of Co and Ni, and has a considerably higher corrosion resistance than that of the conventional magnetic recording medium having a thin Co-Ni magnetic film.

A perpendicular magnetic recording medium according to this invention comprises an electrically conductive underlayer formed on a non-magnetic substrate, in the case where no high permeability magnetic film is deposited, and a magnetic thin film having a perpendicular magnetic anisotrophy is formed thereon. In the case of a so-called double-layer structure including a high permeablilty magnetic film, on the non-magnetic substrate are formed the high permeablilty magnetic film, an intermediate film, and a magnetic thin film one on another in this order. The nearest neighbor's distance of atoms of the underlayer and the intermediate film is not smaller than 0.25 nm (2.5 .ANG.) and not greater than 0.32 nm (3.2 .ANG.) and they are made of at least one selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, Ti, nitrides and oxides of these elements.

Perpendicular magnetic recording medium and fabrication method therefor

A photomask is disclosed which is suitable for use in the one-mask method capable of forming a plurality of patterns with one exposure, and in which an opaque pattern having a predetermined form and a semi-transparent pattern having another predetermined form are formed on a transparent substrate, and the semi-transparent pattern is formed of an opaque film having a large number of fine through holes.

Photomask

The ion implantation is performed in a manner to vary the angle between an ion beam and an article to be implanted with ions, whereby it can be accomplished with remarkable ease while providing the impurity distribution which is flattened in the depthwise direction.

Ion implanting method

Growing community of inventors

Kanagawa, Japan

Norikazu Tsumita