Hitachi, Ltd.

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Maxell, Limited

Hiroaki Nemoto

Ikuko Takekuma

Hiroyuki Nakagawa

Hideki Saga

Yoshiyuki Hirayama

Ichiro Tamai

Hirofumi Sukeda

Takayuki Ichihara

Yuzuru Hosoe

Kimio Nakamura

Hiroyuki Suzuki

Yohji Maruyama

Takehiko Hamaguchi

Kazuetsu Yoshida

Hiroshi Ide

Masahiko Takahashi

Mineaki Kodama

Akemi Hirotsune

Kenchi Ito

Kiwamu Tanahashi

Masukazu Igarashi

Tatsuya Hinoue

Tomohiro Okada

Atsushi Nakamura

Hiroyuki Awano

Fumiko Akagi

Masae Suzuki, Legal Representative

Junichi Sayama

Miki Hara

In one embodiment, a magnetic storage device includes at least one microwave assisted magnetic recording (MAMR) head, each MAMR head including a spin torque oscillator (STO), a magnetic recording medium, a drive mechanism for passing the magnetic medium over the at least one MAMR head, and a controller electrically coupled to the at least one MAMR head for controlling operation of the at least one MAMR head, wherein the magnetic recording medium includes a recording layer positioned directly or indirectly above a substrate and an assist layer positioned above the recording layer, wherein the recording layer includes at least Co, Pt, and an oxide or oxygen, wherein the assist layer is positioned closer to the at least one MAMR head and includes at least Co and Pt, and wherein at least a portion of the recording layer has a smaller anisotropic magnetic field than the assist layer.

Granular media with a high-Hk assist layer for microwave-assisted magnetic recording

A magnetic medium for perpendicular magnetic data recording, having improved magnetic properties through use of a novel seed layer. The magnetic medium includes a substrate having a seed layer, a magnetic under-layer and a magnetic recording layer formed there-over. The seed layer includes an element selected from a first group of Cr, Co, Fe and Ni, and at least one element that is selected from the other elements of the first group or from a second group consisting of W, Mo and Ru. A buffer layer may be included between the substrate and the seed layer.

Perpendicular magnetic recording media having novel seed layer

In order to provide a thermal energy assisted medium capable of improving anti-sliding reliability over long periods of time in low flying head conditions, while also maintaining a high SNR, a unique medium is proposed. A soft magnetic layer is formed on a substrate, a soft magnetic layer is formed thereon via a non-magnetic intermediate layer, and an intermediate layer, a crystal oriented control intermediate layer, an artificial lattice intermediate layer having an artificial lattice film in which a first layer comprising Co and a second layer comprising Pt and Pd are laminated repeatedly to form a recording layer, and a cap layer and an lubricating layer are formed. The concentration of Pd comprising the second layer is from about 20 atomic % to about 40 atomic %. Other mediums and systems are also described.

Thermal energy assisted medium

Embodiments of the present invention help allow accurate control of the magnetization reversal in a magnetic recording layer in small reversal units, whereby high-density recording can be achieved. According to one embodiment, by forming an intermediate layer having a granular structure similar to that of the magnetic recording layer below the magnetic recording layer, a continuous crystal grain boundary is formed at the interface between the magnetic recording layer and the intermediate layer, thereby preventing incomplete formation of the crystal grain boundary found in the initial growth layer of the magnetic recording layer. The intermediate layer comprises a non-magnetic alloy comprising Co and Cr as its main components and an oxide such as Al, Cr, Hf. Mg, Nb, Si, Ta, Ti and Zr. Further, the average content of the oxygen element in the intermediate layer is in the range from 6 at % to 20 at %.

Perpendicular magnetic recording medium and magnetic recording/reproducing apparatus using the same

According to embodiments of the present invention, a shielded pole writer and a perpendicular magnetic recording medium suitable thereto are combined to provide high medium SNR and excellent OW characteristic simultaneously. A perpendicular magnetic recording medium of a magnetic storage apparatus mounting a shielded pole writer, including a perpendicular magnetic recording medium having a recording layer of a three layered structure is used. A first recording layer has a granular structure consisting of grain boundaries containing an oxide and columnar grains comprising a CoCrPt alloy, in which a second recording layer and a third recording layer formed thereabove comprise Co as a main ingredient, contain Cr and do not contain an oxide, and the Cr concentration in the second recording layer is lower than the Cr concentration in the third recording layer.

Magnetic storage apparatus

Surface flatness of magnetic recording medium to which a magnetic recording layer made of L1FePt magnetic alloy thin film, with distance between a magnetic head and a magnetic recording medium sufficiently reduced. The magnetic recording layer includes: magnetic layers containing a magnetic alloy including Fe and Pt as principal materials; and one non-magnetic material selected from carbon, oxide and nitride. The first magnetic layer disposed closer to a substrate has a granular structure in which magnetic alloy grains including FePt alloy as the principal material are separated from grain boundaries including the non-magnetic material as the principal material. The second magnetic layer disposed closer to the surface than the first magnetic layer is fabricated so as to have a homogeneous structure in which an FePt alloy and the non-magnetic material are mixed in a state finer than diameters of the FePt magnetic alloy grains in the first magnetic layer.

Magnetic recording medium including plural FePt alloy layers including carbon, oxides or nitrides

According to one embodiment, a magnetic recording medium includes a magnetic recording layer formed above a substrate, comprising: a first magnetic layer formed from a [Co/Pt]multilayered film, wherein the first magnetic layer has a face-centered cubic (fcc) (111) crystal structure, the (111) direction being perpendicular to a film surface thereof, and a second magnetic layer comprising a CoCrPt or CoCrPt alloy film formed above the first magnetic layer, wherein the second magnetic layer has a hexagonal close packed (hcp) (00.1) crystal structure, the (00.1) direction being perpendicular to a film surface thereof. According to another embodiment, a system includes a magnetic recording medium as described above, a magnetic head for reading from and/or writing to the magnetic recording medium, a magnetic head slider for supporting the magnetic head, and a control unit coupled to the magnetic head for controlling operation of the magnetic head.

[object Object]

To avoid the occurrence of a recording error by suppressing the influence that a magneto-static interaction acting between the pattern dots exerts on a recording process and expand a margin for recording synchronization timing lag or tracking misregistration on the pattern dot. Each pattern dot has a structure in which a plurality of parts having different magnetization reversal fields are bonded with exchange interaction in the in-plane direction of a medium, substrate. The positional relationship between the parts having different magnetization reversal fields is substantially coincident between the adjacent pattern dots, which are arranged to have a gradient of magnetization reversal field in a track direction or track transverse direction. Further, the recording is performed by adapting a gradient of recording magnetic field to the gradient of magnetization reversal field. Other methods and systems are described as well.

Magnetic medium having an artificial pattern structure using a gradient of a magnetization reversal field and a method of use thereof

A thermally assisted magnetic recording medium includes a substrate and at least two, i.e., first and second magnetic recording layers. These layers are hard magnetic layers and contain magnetic grains and a non-magnetic substance magnetically segregating the magnetic grains at grain boundaries. The first magnetic recording layer has a magnetic anisotropy energy K, a grain volume v, and energy for maintaining its recording magnetization Kv; the second magnetic recording layer has a magnetic anisotropy energy K, a grain volume v, and energy for maintaining its recording magnetization Kv; and the ratio Kv/kT of Kvto a thermal fluctuation energy kT, where krepresents a Boltzmann constant and T represents an absolute temperature, and the ratio Kv/kT of Kvto kT satisfy the following conditions: Kv/kT is larger than Kv/kT at room temperature, but is smaller than Kv/kT at temperatures around the Curie temperature of the first magnetic recording layer.

Thermally assisted recording media and system

In an information recording/reproducing method performing a thermo-magnetic recording, a tracking offset value of a recording light spot and/or a tracking offset value of a magnetic flux detecting element is changed in accordance with a radial position at which a tracking is performed at the present time, to make a direction of a magnetic wall of a recording magnetic domain in accord with a longitudinal direction of the magnetic flux detecting element. Alternatively, a shape of a heated area is changed to be in accord with the direction of the magnetic flux detecting means at respective radial position, to make the direction of the magnetic wall of the recording magnetic domain in accord with the longitudinal direction of the magnetic flux detecting element.

Megneto-optical recording device capable of changing the shapes of heating areas

Embodiments in accordance with the present invention provide a perpendicular recording medium with low noise and high recording density by reducing the effects from noise generated from the vicinity of the interface with the intermediate layer of the recording layer, in a perpendicular recording medium utilizing a granular recording layer containing oxygen or oxide additive in a cobalt-chromium alloy formed on an intermediate layer with a ruthenium or ruthenium alloy layer. A first recording layer and a second recording layer are formed in order on an intermediate layer of ruthenium or ruthenium alloy. The first recording layer and the second recording layer are comprised of cobalt as the main material in a granular structure containing chromium and oxygen. The saturation magnetization of the first recording layer is lower than the saturation magnetization of the second recording layer. When a first recording layer saturation magnetization is set as Ms(emu per cubic centimeter), a second recording layer saturation magnetization is set as Ms(emu per cubic centimeter), and the first recording layer film thickness is set to t(nm), then (Ms&#x2212;Ms)&#xd7;twill be larger than 0 (memu per square centimeter) and smaller than 0.15 (memu per square centimeter).

Perpendicular magnetic recording medium and magnetic storage apparatus using the same

Magneto-optical recording device capable of changing the shapes of heating areas

Disclosed are a perpendicular magnetic recording medium with lower medium noise, insusceptible to thermal fluctuation and high recording resolution and a method of manufacturing it. As the step of forming a metal layer at the time of forming a recording layer on a non-magnetic substrate via a plurality of underlayers and the step of forming an oxide layer with an average thickness of 0.2 nm or less are repeated, the crystal grains are magnetically isolated without disturbing the orientation of the crystal grain of the recording layer of the perpendicular magnetic recording medium or without degrading the magnetic characteristic of the crystal grain of the recording layer.

Perpendicular magnetic recording medium and method of manufacturing it

A perpendicular magnetic recording medium includes an intermediate film formed of a plurality of layers between a soft magnetic film and a perpendicular magnetization film. The intermediate film includes at least two layers, i.e., an oxygen-containing layer, or a nonmetallic element-containing layer containing nitrogen, silicon or carbon, and a metallic layer formed on a surface side of the oxygen-containing layer or the nonmetallic element-containing layer. The metallic layer includes a plurality of isolated island-shaped structures. Crystal grains of the perpendicular magnetization film are formed so as to correspond to the isolated island-shaped structures. As a result, a high recording density is obtained.

Perpendicular magnetic recording media

Embodiments in accordance with the present invention provide a perpendicular magnetic recording medium which is easy to record, offers superior thermal stability of recording magnetization, and allows high-density recording. In one embodiment, a perpendicular magnetic layer with controlled magnetic properties is used as a magnetic storage layer of a perpendicular magnetic recording medium, the magnetic properties having been controlled such that an indicator &#x3c3;h[%] of the dispersion of magnetization switching fields in the perpendicular magnetic layer and an indicator D[nm] of the intensity of exchange interactions, in film surface directions, in the perpendicular magnetic layer satisfy inequalities &#x3c3;h/27+D/90&#x3c;1, and D&#x3e;20. The indicators can be measured using a magnetometer.

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Kanagawa, Japan

Hiroaki Nemoto