Hitachi, Ltd.

Akira Osaki

Yoshihiro Shiroishi

Yotsuo Yahisa

Yuzuru Hosoe

Tomoo Yamamoto

Akira Ishikawa

Kiwamu Tanahashi

Yoshiki Kato

Heigo Ishihara

Jun Fumioka

Masatoshi Takeshita

Masaki Ohura

Waichi Nagashiro

Fuzio Maeda

Yukio Katoh

Masukazu Igarashi

Kazuetsu Yoshida

Shinji Narishige

Naoki Kodama

Futoshi Tomiyama

Katsuo Abe

Tomoyuki Ohno

Takanori Kudo

Emi Mangyo

Yuichi Ootani

A head suspension assembly having a magnetic head, an arm which is supported so as to rotate, a suspension having one end which is fixed to an end of the arm and an other end which mounts the magnetic head, a nonvolatile memory which is mounted on the suspension assembly, and stores control parameters of the magnetic head, a connecting terminal which is mounted to the arm, and a signal transmission line which electrically connects the connecting terminal to the nonvolatile memory and the magnetic head. The connecting terminal enables transmission of signals at least one of to and from the head suspension assembly, the nonvolatile memory and the magnetic head.

Head suspension assembly mounting nonvolatile memory and magnetic disk device

A head suspension assembly has an arm supported so as to rotate, an elastically flexible suspension having one end which is fixed to an end of the arm and the other end has a magnetic head mounted thereon, and a signal transmission line fixed on the suspension and the arm which connects the magnetic head with a main FPC. A head amplifier which transmits and receives signals to and from the magnetic head, and a nonvolatile memory which stores optimized control parameters of the magnetic head and the head amplifier, are mounted together on the head suspension assembly; and, the head amplifier and the nonvolatile memory are electrically connected to the signal transmission

In a magnetic recording medium having a non-magnetic disk substrate and a magnetic film formed on the surface of the non-magnetic disk substrate, a surface average roughness factor Ra(r) on the surface of the medium being from 0.3 nm to 3 nm, an orientation ratio of coercivity being from 0.1 to 0.7, and an in-plane magnetic anisotropic energy being from 3.times.10.sup.4 J/m.sup.3 to 5.times.10.sup.5 J/m.sup.3. By using such a medium, it is possible to provide a magnetic recording apparatus in which the magnetic head is capable of flying in a low position and high-density recording is achieved.

Magnetic recording media and magnetic recording system using the same

A magnetic recording medium includes a non-magnetic substrate, and a magnetic layer provided on the non-magnetic substrate. The value of the product Br.sub.1 .delta. of the residual flux density Br.sub.1 of the magnetic layer determined in a recording direction and the thickness .delta. of the magnetic layer is not less than 5 G.mu.m and not more than 180 G.mu.m; the value of the ratio of Br.sub.1 to the residual flux density Br.sub.2 determined in a direction parallel to the substrate plane and perpendicular to the recording direction, Br.sub.1 /Br.sub.2, is not less than 1.3 and not more than 3; the surface of the non-magnetic substrate has texture grooves therein extending predominantly in the recording direction; and the average roughness factor Ra of the surface of the magnetic layer determined in a direction perpendicular to the substrate plane and perpendicular to the recording direction is not less than 0.3 nm and not more than 1.9 nm. Alternatively, the value of the product Br.delta. of the residual flux density Br of the magnetic layer determined in the recording direction and the thickness .delta. of the magnetic layer is not less than 5 G.mu.m and not more than 80 G.mu.m; and the value of the anisotropic magnetic field H.sub.k of the magnetic recording medium is not less than 7 kOe and not more than 20 kOe.

Magnetic recording medium, process for producing the same and magnetic

In a magnetic recording medium having a nonmagnetic disk substrate and a magnetic film formed on the surface of the non-magnetic disk substrate, a surface average roughness factor Ra(r) on the surface of the medium being from 0.3 nm to 3 nm, an orientation ratio of coercivity being from 0.1 to 0.7, and an in-plane magnetic anisotropic energy being from 3.times.10.sup.4 J/m.sup.3 to 5.times.10.sup.5 J/m.sup.3. By using such a medium, it is possible to provide a magnetic recording apparatus in which the magnetic head is capable of flying in a low position and high-density recording is achieved.

In a magnetic recording system including magnetic recording media, a rotation driving unit for driving these magnetic recording media, read/write magnetic heads, driving apparatus for driving these read/write magnetic heads, and a read/write signal processing apparatus, a reading portion of the respective magnetic heads is arranged by a magnetoresistive head. The magnetic recording media are constructed of multi-layered magnetic media having a plurality of magnetic layers fabricated directly, or via underlayers on a non-magnetic disk substrate, and of non-magnetic intermediate layers arranged among these non-magnetic layers. Furthermore, one coercivity which is measured by applying a magnetic field along a circumferential direction of the magnetic recording media, is selected to be larger than the other coercivity which is measured by applying a magnetic field along a radial direction of the magnetic recording media, so that a higher signal-to-noise ratio is achieved, as compared with that of the conventional magnetic recording system. Since the thickness of the non-magnetic intermediate layers is smaller than or equal to 5 nm, and also the total layer is smaller than or equal to 5 nm, and also the total layer number of the plural magnetic layers is selected to be odd, better characteristics can be achieved. Accordingly, since the MTBF (Mean Time Before Failure) is longer than or equal to 0.15 million hours with high recording density, and the disk substrate and the magnetic head sliders can be mounted at high packaging density, a compact and high-capacity magnetic recording system can be obtained.

Multi-layered magnetic recording medium and magnetic recording system

A magnetic recording medium used in a magnetic recording apparatus has a non-magnetic substrate, a magnetic film formed on the substrate, an optional protective film formed on the magnetic film and a lubricating layer formed on the top surface of the medium. The lubricating layer is made of an organic polymer lubricant having molecules with an interstitial radius of not more that 0.31 nm. The interstitial radius is affected by coating the lubricant on the protective film after the protective film has been cleaned with a surface treatment, such as an oxygen plasma treatment or an ozone treatment. By maintaining the interstitial radius between molecules of the lubricant layer equal to or less than 0.31 nm, water and corrosive molecules in water cannot penetrate the lubricating layer and corrode the magnetic film. Also, the lubricant layer provides good sliding durability with a resultant long CSS life.

Magnetic recording medium and magnetic recording apparatus

A magnetic recording medium comprising a substrate and, formed thereon, a magnetic layer comprised of magnetic particles bonded to each other with a thermosetting binder can be improved with respect to the durability by forming a number of fine pores in the magnetic layer and impregnating the fine pores with a lubricant. Particularly, when the fine pores have a diameter of 0.2 .mu.m or less and a rate of the fine pore in area of 3 to 30%, the durability can be improved while maintaining the noise during the recording and reproduction of information on a low level. In preparing the magnetic recording medium having such fine pores, it is preferred that an easily thermal-decomposable additive, such as polyalkylene oxide, be added to a magnetic layer forming paint. A magnetic recording medium having further improved characteristics can be produced by interposing an undercoating layer having a number of fine pores between the magnetic layer and the substrate, allowing the fine pores in the undercoating layer to communicate with the fine pores in the magnetic layer and impregnating the fine pores with a lubricant. In this case, in forming the fine pores, it is preferable to add an easily thermal-decomposable additive to a paint or extract a thermoplastic resin from a layer containing the thermoplastic resin with a solvent.

Magnetic recording medium and method for producing the same

A magnetic recording medium comprising a substrate and, formed thereon, a magnetic layer comprised of magnetic particles bonded to each other with a thermosetting binder can be improved with respect to the durability by forming a number of fine pores in the magnetic layer and impregnating the fine pores with a lubricant. Particularly, when the fine pores have a diameter of 0.2 .mu.m or less and a rate of the fine pore in area of 3 to 30%, the durability can be improved while maintaining the noise during the recording and reproduction of information on a low level. In preparing the magnetic recording medium having such fine pores, it is preferred that an easily thermal-decomposable additive, such as polyalkylene oxide, be added to a magnetic layer forming paint. A magnetic recording medium having further improved characteristics can be produced by interposing an undercoating layer having a number of fine pores between the magnetic layer and the substrate, allowing the fine pores in the undercoating layer to communicate with the fine pores with a lubricant. In this case, in forming the fine pores, it is preferable to add an easily thermal-decomposable additive to a paint or extract a thermoplastic resin from a layer containing the thermoplastic resin with a solvent.

A magnetic recording medium is prepared by applying a magnetic paint containing at least magnetic particles and a thermally curable binder to a substrate, thermally curing the applied magnetic paint, thereby forming a magnetic film, and impregnating micropores formed in the magnetic film with a lubricant, where the magnetic paint further contains a poly(alkyleneoxide)-grafted binder, and the grafted poly(alkyleneoxide) moiety is thermally decomposed during the thermal curing, thereby forming the micropores in the magnetic film. A large number of micropores having a pore size of not more than 0.1 .mu.m are formed in the magnetic film, and a magnetic disk of high durability with less noises and errors during the recording and reproduction can be obtained.

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Odawara, Japan

Akira Osaki