Hitachi, Ltd.

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies Japan, Ltd.

Hgst Netherlands, B.v.

Tomoo Yamamoto

Yuzuru Hosoe

Akira Ishikawa

Ichiro Tamai

Nobuyuki Inaba

Kiwamu Tanahashi

Yotsuo Yahisa

Masaaki Futamoto

Tetsuya Kanbe

Masukazu Igarashi

Yoshibumi Matsuda

Kazusuke Yamanaka

Yoshihiro Shiroishi

Tatsuya Hinoue

Yoshio Takahashi

Shinji Narishige

Kenji Furusawa

Yasutaro Uesaka

Hiroyuki Kataoka

Hidekazu Kashiwase

Akira Osaki

Emi Mangyo

Hiroyuki Suzuki

Yoshiki Kato

Toshinori Ono

Shinji Fukaya

Naoto Endo

Jun Fumioka

Kazuhiro Ura

Yoshifumi Matsuda

Kazuetsu Yoshida

Teruaki Takeuchi

Masatoshi Takeshita

Masaki Ohura

Joe Inagaki

Yukio Katoh

Hiroshi Ikeda

Atsushi Nakamura

Naoki Kodama

Futoshi Tomiyama

Yukio Kato

Sadao Hishiyama

Tomoyuki Ohno

Katsuo Abe

Fumiko Akagi

Masae Suzuki, Legal Representative

Jo Inagaki

Takuya Kojima

Das Sarbanoo

Hiroyuko Suzuki

Embodiments of the present invention provide a perpendicular magnetic recording medium with less medium noise, excellent overwrite characteristics, and scratch resistance. According to one embodiment, when an Ar gas with addition of a micro-amount of oxygen is used upon forming an upper Ru intermediate layer, a micro-structure of a magnetic layer formed thereon can be formed in a state where no magnetic oxide region is segregated and the magnetic crystal grains are isolated. In this case, a gas pressure for forming the upper intermediate layer is set to 5 Pa or more and 12 Pa or less which is a region much higher compared with 0.5 Pa or more and 1 Pa for the lower Ru intermediate layer. Since writing by a head becomes difficult remarkably in the perpendicular magnetic medium having magnetic crystal grains promoted for isolation, a second magnetic layer for facilitating magnetization reversal by lowering the oxide concentration and somewhat strengthening coupling between particles only in the magnetic layer on the side of the surface is formed to a layer above the first magnetic layer as a main part.

Perpendicular magnetic recording medium and manufacturing method thereof

In one embodiment, a magnetic recording medium comprises an underlying film, a magnetic film and a protective film formed in this order on a substrate. The magnetic film is a cobalt-base alloy film containing chromium and has a plurality of magnetic layers stacked without interposition of any non-magnetic layer. The plural magnetic layers comprise first, second and third magnetic layers. The first magnetic layer is disposed between the underlying film and the second magnetic layer. The second magnetic layer is disposed between the first magnetic layer and the third magnetic layer. The third magnetic layer is disposed between the second magnetic layer and the protective film. The concentration of chromium contained in the first magnetic layer is lower than that of chromium contained in the second magnetic layer. The thickness of the first magnetic layer is smaller than that of the second magnetic layer. The magnetic layers which overlie the first magnetic layer further contain platinum and boron. The concentration of chromium contained in the third magnetic layer is lower than that of chromium contained in the second magnetic layer.

Magnetic recording medium having a cobalt-based alloy film for high density recording and magnetic storage device using same

An AFC magnetic recording medium having a three-layered ferromagnetic structure capable of reducing noises without deteriorating thermal stability is provided in order to achieve ultra-high recording density. In one embodiment, the AFC magnetic recording medium has a magnetic recording layer formed on a substrate via an underlayer, the magnetic recording medium consisting of a first ferromagnetic layer formed on the underlayer, a second ferromagnetic layer formed on the first ferromagnetic layer via a nonmagnetic layer inducing the antiferromagnetic interaction, and a third ferromagnetic layer formed on the second ferromagnetic layer, wherein the center of gravity G of the magnetic recording medium is defined using the distance tfrom the upper surface of the third ferromagnetic layer as:

Magnetic recording media with ultra-high recording density

A longitudinal magnetic recording medium having a high medium S/N, with no problems in view of the overwrite characteristic, excellent in the bit error rate and sufficiently stable also to thermal fluctuations is provided. In one embodiment, a first underlayer, second underlayer, and a third underlayer are formed on a substrate and, further, a first magnetic layer, a spacer layer including Ru as a main ingredient, a second magnetic layer, and a third magnetic layer are formed in adjacent with each other in this order. The thickness of the second magnetic layer is made larger than the thickness of the third magnetic layer and the total for the concentrations of cobalt and platinum obtained in the second magnetic layer is not more than the total for the concentrations of cobalt and platinum contained in the third magnetic layer.

Magnetic recording medium and magnetic memory device for high density recording

A magnetic recording medium capable of attaining high in-plane recording density of 100 Mbits or more per 1 mmis provided. Magnetic recording medium is provided in which underlayers, a first magnetic layer, a first intermediate layer, a second magnetic layer, a second intermediate layer, a third magnetic layer, a protection layer and lubrication layer are formed in this order above a substrate. Each of the third magnetic layer and the second magnetic layer comprises a Co-based alloy containing at least Pt, Cr and B. The concentration of Pt contained in the second magnetic layer is not more than that in the third magnetic layer.

Longitudinal multi-layer magnetic recording medium

A large-capacity, low-cost, longitudinal magnetic recording medium capable of ultra-high-density recording of 70 Gigabits or more per square inch is disclosed. The longitudinal magnetic recording medium of the present invention comprises a first seed layer, a second seed layer, a first underlayer, a second underlayer, and a magnetic layer, which are formed on a nonmagnetic substrate in this order. A material containing at least Al and any one of Ru and Re is used to form the second seed layer, and a material containing at least any one of Co and Ni and one or both of Al and Ti is used to form the first underlayer. It is also possible to use Cr or a Cr alloy containing Cr and at least one element selected from the constituent element group A consisting of Ti, Mo, and W for forming the second seed layer.

Magnetic recording medium

A magnetic recording medium having a substrate, an under-layer formed on the substrate, a magnetic layer formed on the substrate and a protective layer formed on the magnetic layer. The magnetic layer comprises Co, Cr and Pt with a thickness being from 10 nm to 22 nm. Further, a coercivity of the magnetic layer is not less than 2000 Oe, and a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe.

Magnetic recording medium and magnetic recording and reproducing apparatus

A magnetic recording medium which comprises a substrate, an orientation control layer formed directly thereon, and a Co alloy magnetic layer formed thereon directly or indirectly with a Cr underlayer or Cr alloy underlayer interposed between them, the orientation control layer having an L10 crystal structure, L21 crystal structure, fcc crystal structure, or B2 (CsCl) crystal structure containing B, owing to this construction, has a high coercive force and a low noise level and is only slightly vulnerable to thermal fluctuation. A magnetic storage device having a magnetic recording medium, a driver to turn said magnetic recording medium in the recording direction, a magnetic head including a recording element and a read-back element, means to move the magnetic head relative to the magnetic recording medium, and a record-read signal processing means to perform waveform processing on input signals to and output signals from the magnetic head, uses this magnetic recording medium and has a magnetoresistive effect read-back element in its magnetic head. This magnetic storage device has a recording density in excess of 3 Gbit/in.

Magnetic recording medium and magnetic storage device

A magnetic recording system includes an in-plane magnetic recording medium having a magnetic layer fabricated on a single underlayer or on a plurality of underlayers respectively fabricated on a substrate; a driver unit for driving the in-plane magnetic recording medium in a write direction; a magnetic head having a read unit and a write unit; a unit for moving the magnetic head relative to the in-plane magnetic recording medium; and a read/write signal processing unit for reading an output signal from the magnetic head and writing an input signal to the magnetic recording media, wherein the read unit of the magnetic head is a magnetoresistive head and the single underlayer or at least one of the plurality of underlayers is made of Co-containing amorphous material or fine crystal material, or is made of alloy material, the alloy material having as the main components at least one element selected from a group consisting of Cr, Mo, V and Ta and containing at least one element selected from a group consisting of B, C, P and Bi. The magnetic recording system can be realized which can read and write high density information and have high reliability.

Magnetic recording media and magnetic recording system using the same

A large-capacity magnetic storage apparatus is disclosed, capable of performing ultra-high density magnetic recording of 50 gigabits or more per 1 square inch. In a perpendicular magnetic recording medium having a non-magnetic intermediate layer and a magnetic recording layer sequentially formed, the non-magnetic intermediate layer is composed of a layer having a face-centered cubic structure and containing a non-magnetic elements excluding Pt. Specifically, the intermediate layer mainly contains at least one selected from the group of elements constituted of Al, Cu, Rh, Pd, Ag, Ir and Au, and is composed of a film having a face-centered cubic (f. c. c.) structure. The magnetic recording layer contains at least Co, Cr and Pt, and is composed of a film having a hexagonal close-packed (h. c. p.) structure. More preferably, a non-magnetic h. c. p. intermediate layer is provided between the non-magnetic intermediate layer and the magnetic recording layer.

Perpendicular magnetic recording medium and magnetic storage apparatus using the same

An ferromagnetic thin film is used to provide a magnetic recording medium whose noise is low and whose S/N value is high. The ferromagnetic thin film as the magnetic film of the magnetic recording medium is such that the fluctuation field of magnetic viscosity at 25&#xb0; C. at the field strength equal to remanence coercivity or coercivity is not less than 15 oersteds and the coercivity is not less than 2000 oersteds.

Magnetic recording medium possessing a fluctuation field of not less than 30 Oe

To obtain a large capacity magnetic recording medium capable of recording at a super high density of 3 Gbit or more per one square inch and a magnetic storage apparatus, a magnetic recording medium is prepared by disposing orientation control layers &prime; having at least a B2 (CsCl) structure on a substrate , disposing a first underlayer comprising Cr and a second underlayer containing at least one element selected from Cr, Nb, Mo, Ta, W and Ti and having a lattice constant greater than that of the first underlayer and then forming a magnetic layer comprising Co as the main ingredient. A magnetic storage apparatus is constituted by combining the magnetic recording medium, a magnetic head comprising a recording system and a read out system opposed to each of the surfaces of the magnetic recording medium, a unit for moving the magnetic head relative to the magnetic recording medium and a read/write signal processing system for waveform processing of input signals and output signals to and from the magnetic head.

Longitudinal magnetic recording media

It is an object of the present invention to provide a magnetic recording medium which has a high level of magnetic antisotropy energy, retains stably the state of recording magnetization within the operating temperature range and is suitable for high-density recording with a low noise level, and a magnetic storage device for the magnetic recording medium. For attaining the above object, the magnetic recording film of the magnetic recording medium is characterized in that its magnetic anisotropy energy constant K at an absolute temperature of 300 K is greater than 3.6&times;10 erg/cc and the average particle diameter is larger than 5 nm and smaller than 12 nm.

Method of manufacturing a magnetic recording media

Growing community of inventors

Hachioji, Japan

Tomoo Yamamoto