Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Hgst Netherlands, B.v.

Hitachi Global Storage Technologies Netherlands B.v.

Ichiro Tamai

Yuzuru Hosoe

Kiwamu Tanahashi

Tomoo Yamamoto

Tetsuya Kanbe

Yoshio Takahashi

Akira Ishikawa

Yoshiyuki Hirayama

Ikuko Takekuma

Hiroaki Nemoto

Hiroyuki Nakagawa

Yotsuo Yahisa

Satoshi Matsunuma

Takayuki Ichihara

Yoshibumi Matsuda

Masukazu Igarashi

Fumiyoshi Kirino

Toshinori Ono

Hiroyuki Kataoka

Nagatugu Koiso

Shinji Fukaya

Naoto Endo

Yoshifumi Matsuda

Kazuhiro Ura

Masaaki Futamoto

Akemi Hirotsune

Yoshihiro Shiroishi

Nobuyuki Inaba

Reiko Arai

Kazusuke Yamanaka

Mineaki Kodama

Emi Mangyo

Hiroshi Ikeda

Tatsuya Hinoue

Yoshinori Honda

Shun Tonooka

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

In one embodiment, a perpendicular magnetic recording medium includes an oxide recording layer including an oxide and a non-oxide recording layer which does not contain an oxide positioned above the oxide recording layer. The oxide recording layer includes a region Rwhere a grain boundary width in a direction parallel to a plane of formation of Rincreases therealong from a lowermost portion of the oxide recording layer toward a medium surface, a region Rpositioned above Rwherein a grain boundary width increases therealong toward the medium surface, a region Rwhere a grain boundary width of Rdecreases therealong from Rto R, with Rbeing positioned between Rand R, and a region Rwhere a grain boundary width of Rdecreases therealong from Rtoward the medium surface, with Rbeing positioned above Rand near an uppermost portion of the oxide recording layer.

Perpendicular magnetic recording medium with grain boundary controlling layers

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 one embodiment, a PMRM includes a substrate, a soft magnetic underlayer above the substrate, an underlayer above the soft magnetic underlayer, an oxide-containing magnetic layer above the underlayer, and a ferromagnetic layer above the magnetic layer having no oxides. The underlayer controls orientation and segregation of the magnetic layer. The oxide-containing magnetic layer comprises at least two or more magnetic layers, a Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer is between about 23 at. % and about 32 at. %, and a difference between the Cr concentration of the magnetic layer adjacent to the ferromagnetic metal layer and a magnetic layer having a lowest Cr concentration among the at least three magnetic layers is less than about 25 at. %, the magnetic layer with a lowest Cr concentration has a granular structure, and a nucleation field is greater than about 159.2 kA/m.

Perpendicular magnetic recording medium (PMRM) and magnetic storage device using the same

According to one embodiment, a perpendicular magnetic recording medium includes a soft magnetic underlayer formed above a substrate, a lower seed layer formed above the soft magnetic underlayer, at least one upper seed layer formed above the lower seed layer, an interlayer formed above the at least one upper seed layer, a perpendicular recording layer formed above the interlayer, and a protective layer formed above the perpendicular recording layer, wherein the at least one upper seed layer comprises Ni or a Ni based alloy including N, and wherein the lower seed layer includes Ni and at least one element selected from a group consisting of: W and Cr. Other embodiments are described herein regarding perpendicular magnetic recording systems and methods of producing perpendicular magnetic media.

Perpendicular magnetic recording medium and magnetic storage apparatus using the same

In one embodiment, a perpendicular magnetic recording medium includes a substrate, a soft-magnetic underlayer above the substrate, a seed layer above the soft-magnetic underlayer, a first intermediate layer above the seed layer, a second intermediate layer above the first intermediate layer, a recording layer above the second intermediate layer, and a protective layer above the recording layer. The second intermediate layer includes an Ru alloy having an element selected from a group consisting of: Ti in a range from about 20 at. % to about 50 at. %, Nb in a range from about 20 at. % to about 50 at. %, Al in a range from about 20 at. % to about 40 at. %, Ta in a range from about 30 at. % to about 50 at. %, and Si in a range about 20 at. % to about 40 at. %. Other magnetic media and systems using this media are described according to more embodiments.

Perpendicular magnetic recording media having low medium noise and systems using the same

Embodiments of the present invention provide a perpendicular magnetic recording medium that reduces the noise of granular recording layers, obtains sufficient overwrite characteristic that suppresses an increase in the magnetic cluster size, and allows high-density recording. According to one embodiment, a perpendicular magnetic recording medium comprising substrate having thereon at least soft magnetic layer, nonmagnetic intermediate layer, a perpendicular recording layer and protective layer formed in that order. The perpendicular recording layer consists of three or more layers of first recording layer, a second recording layer, and a third recording layer from the side nearer to the substrate. The first recording layer and the second recording layer have a granular structure comprising a grain boundary of an oxide surrounding ferromagnetic crystal grains containing Co and Pt, and the third recording layer has a non-granular structure mainly comprising Co and not containing an oxide. The grain boundary of the first recording layer contains Si, Cr and oxygen, and at least one element selected from Ti, Ta and Nb, and the grain boundary of the second recording layer contains Cr and oxygen, or contains Cr and oxygen and at least one element selected from Si, W and V.

Perpendicular magnetic recording medium and magnetic storage device using the same

Embodiments in accordance with the present invention help to obtain a perpendicular magnetic recording medium having a granular structure, excellent recording/reproducing properties, and excellent durability. According to one embodiment, a recording layer includes a layer which has crystal grains mainly composed of cobalt and crystal grain boundaries mainly composed of the oxide; the oxygen content of the recoding layer is changed in the film thickness direction; the oxygen content in the area in the vicinity of the interface between the recording layer and the intermediate layer is made lower than the oxygen content in the area in the vicinity of the center of the recording layer; and the oxygen content in the area in the vicinity of the interface between the recording layer and the protective layer is made lower than the oxygen content in the area in the vicinity of the center of the recording layer.

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).

Embodiments of the embodiment are directed to reducing the inter-granular exchange coupling of an oxide granular medium and obtaining a high media S/N value, resulting in an areal recording density greater than 23 gigabits per square centimeter or more being achieved. In one embodiment, a magnetic recording medium comprises a structure laminating a soft-magnetic underlayer, a lower intermediate layer including Ru, an upper intermediate layer consisting of Ru crystal grains and oxide crystal grain boundaries, a magnetic recording layer consisting of crystal grains and oxide crystal grain boundaries, in order, on a substrate, growing crystal grains of the magnetic recording layer epitaxially on the Ru crystal grains of the upper intermediate layer, and growing the crystal grain boundaries of the magnetic recording layer on the crystal grain boundaries of the upper intermediate layer.

Perpendicular magnetic recording medium and manufacturing of the same

In a granular magnetic recording layer of a perpendicular magnetic recording medium, media noises are reduced by separating adequately magnetic crystal grains and non-magnetic grain boundary and decreasing magnetic exchange interactions among the magnetic crystal grains without causing damage to magnetic anisotropy of the magnetic crystal grains. In one embodiment, the perpendicular magnetic recording medium, in which crystal alloy grains containing Co, Pt, and Cr, and non-magnetic grain boundary containing Si and O is included; the ratio of the number of O atom to that of Si atom in the magnetic recording layer is between about 2.5 and 5; the Si atomic composition in the magnetic recording layer is between about 3 and 6 atomic %; and the O atomic composition in the magnetic recording layer is between about 12 and 20 atomic %, is used. The in-plane distribution of perpendicular coercivity at any points of the medium of the magnetic recording layer is made at most about &#xb1;10% of an average value.

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

Embodiments of the invention provide a perpendicular magnetic recording medium capable of reconciling a high recording density with high thermal stability, and having a high write-ability while maintaining high magnetic anisotropy energy. In one embodiment, a perpendicular magnetic recording medium has a soft-magnetic underlayer, and magnetic recording layers, and the magnetic recording layers comprises a first recording layer containing magnetic grains oriented in a direction normal to a medium plane, and a second recording layer containing magnetic grains tilted in a cross-track direction. There can be provided a perpendicular magnetic recording medium resistant to thermal fluctuation, small in medium noise, and excellent in write-ability.

Magnetic recording medium containing first and second recording layers, each layer containing a columnar structure

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

A magnetic recording medium having a high coercive force and being capable of high-density writing/reading has a substrate, a soft magnetic layer, a non-magnetic intermediate layer, a magnetic layer, a protective layer, and a lubricating layer. The magnetic layer is characterized by stacking fault density and dispersion of particle diameters. The stacking fault density should preferably be no larger than 0.05, and the dispersion of particle diameters should preferably be no larger than 0.4. The magnetic recording medium has a coercive force larger than 4000 Oe, is highly stable to thermal decay, and has a recording density in excess of 50 Gbit/in.

Growing community of inventors

Hachioji, Japan

Ichiro Tamai