Hitachi, Ltd.

Hitachi Maxell, Limited

Hitachi Global Storage Technologies Japan, Ltd.

Hitachi Construction Machinery

Yukio Honda

Masaaki Futamoto

Yoshiyuki Hirayama

Kazuetsu Yoshida

Atsushi Kikugawa

Nobuyuki Inaba

Kiwamu Tanahashi

Kenya Ito

Mikio Suzuki

Toshiyuki Aida

Atsushi Nakamura

Yuzuru Hosoe

Yoshibumi Matsuda

Sumio Hosaka

Ushio Kawabe

Noboru Shimizu

Shigehiko Yamamoto

Sadanori Taguchi

Teruaki Takeuchi

Tsuyoshi Hasegawa

Shigeyuki Hosoki

Hiroyuki Suzuki

Kazumasa Takagi

Isamu Yuito

Akira Ishikawa

Yasutaro Uesaka

Takashi Nishimura

Masakazu Ichikawa

Hajime Koyanagi

Atsushi Kikukawa

Shunji Maeda

Shinji Tanaka

Kazuo Sato

Yoshimi Kawanami

Hitoshi Kubota

Yoshinori Nakayama

Yoshihiro Shiroishi

Shinichiro Saito

Hiroshi Okano

Hideo Fujiwara

Shigeo Ohashi

Akira Shimase

Takeshi Harada

Masahiko Hiratani

Kazuo Shiiki

Mikio Ichihashi

Toshio Hatada

Hiroyuki Awano

Akira Misumi

Toshio Niihara

Tokuumi Fukazawa

Takao Kawamura

Noriyuki Ashiwake

Fumikazu Itoh

Satoshi Haraichi

Heigo Ishihara

Hideo Daimon

Norikazu Tsumita

Katsuki Miyauchi

Kazusuke Yamanaka

Osamu Kitakami

Seiichi Asada

Takanobu Takayama

Hiroshi Fukushima

Yuuichi Madokoro

Toyoji Okuwaki

Hitoshi Iwata

Hironobu Matsui

Mitsuhiro Shikida

Yoshimasa Kondo

Kazushige Imagawa

Shiji Okazaki

Kiyosi Nagasawa

Toshiyuki Aita

Yoshio Degawa

Norio Shibata

Selichi Asada

A perpendicular magnetic recording medium which has been improved to be suitable for high-density magnetic recording and a magnetic recording apparatus using the medium are provided. The magnetic back film of a dual-layer perpendicular recording medium is caused to be constituted by a plurality of layers, and a keeper layerfor keeping perpendicular magnetization and layersandfor improving the recording efficiency of a recording head are functionally separated from one another. Further, the magnetization orientations of the soft magnetic films excluding the keeper layer are defined to be in the circumferential direction of the disk, whereby the frequency of occurrence of noise is decreased.

Perpendicular magnetic recording media, magnetic recording apparatus

There is provided a perpendicular magnetic recording medium comprising a non-magnetic layer having a face-centered cubic structure, an antiferromagnetic layer provided on the non-magnetic layer, a soft magnetic underlayer provided on the antiferromagnetic layer, and a perpendicular recording layer provided on the soft magnetic underlayer, which magnetic recording medium makes it possible to realize a recording density not less than 50 Gb/inand makes the error rate thereof low while suppressing the spike noise.

Perpendicular magnetic recording media

Provided are a double-layer perpendicular magnetic recording medium having a high medium S/N at an areal recording density of 50 Gbits or more per square inch, and a magnetic storage apparatus having excellent reliability with a low error rate. The perpendicular magnetic recording medium is formed by sequentially laminating a domain control layer, an amorphous soft magnetic underlayer, an intermediate layer, and a perpendicular recording layer on a substrate. The domain control layer is a triple-layer film formed by laminating a first polycrystalline soft magnetic layer, a disordered antiferromagnetic layer, and a second polycrystalline soft magnetic layer from a substrate side.

Perpendicular magnetic recording media, manufacturing process of the same, and magnetic storage apparatus using the same

A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/inor higher and a magnetic storage apparatus with a lower error rate and excellent reliability are provided. In a perpendicular magnetic recording medium in which a soft magnetic underlayer, an intermediate layer, and a perpendicular magnetic recording layerare sequentially formed on a substrate, the intermediate layeris made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayeris constituted of ferromagnetic nan-crystals precipitated by annealing.

Perpendicular magnetic recording media and magnetic storage

An object is to automatically detect the positions of spike noise, create a distribution diagram, and perform pass/fail decisions. The cross-correlation function of the signal waveform from a magnetic headand a reference waveform simulating spike noise is used in extraction of spike noise. The number of peaks in the cross-correlation function exceeding a threshold value is counted, and quantitative evaluation of spike noise is performed.

Method for testing or recording servo signal on perpendicular magnetic recording media

Disclosed are a double-layer perpendicular magnetic recording medium having a high medium S/N at a recording density of 50 Gbit or more per square inch and a magnetic storage apparatus with high reliability, which shows a low error rate. In the perpendicular magnetic recording medium in which a pre-coating layer, a soft magnetic underlayer, an intermediate layer, and a perpendicular recording layer are sequentially formed on a substrate, the soft magnetic underlayer contains Fe, Ta and C as main components, a Ta concentration is set to a range from 8 at % to 15 at % , and a ratio of a C concentration to the Ta concentration (C concentration/Ta concentration) is set to a range from 0.5 to 0.9.

Perpendicular magnetic recording media and magnetic storage apparatus using the same

There is provided a perpendicular magnetic recording medium comprising a non-magnetic layer having a face-centered cubic structure, an antiferromagnetic layer provided on the non-magnetic layer, a soft magnetic underlayer provided on the antiferromagnetic layer, and a perpendicular recording layer provided on the soft magnetic underlayer, which magnetic recording medium makes it possible to realize a recording density not less than 50 Gb/in and makes the error rate thereof low while suppressing the spike noise.

Perpendicular magnetic recording medium and magnetic recording apparatus

A double layer perpendicular magnetic recording medium having a high medium S/N ratio at a recording density of 50 Gb/in or higher and a magnetic storage apparatus with a lower error rate and excellent reliability are obtained with a structure having soft magnetic underlayer , an intermediate layer and a perpendicular magnetic recording layer are sequentially formed on a substrate . The, intermediate layer is made to be a non-magnetic amorphous alloy, in which Ni is a main component and Zr is contained, and the soft magnetic underlayer is constituted of ferromagnetic nano-crystals precipitated by annealing.

Magnetic recording medium includes at least two layers having different magnetic anisotropy constants formed on a substrate and the perpendicular magnetic anisotropy of the second magnetic film of those magnetic films, far from the substrate surface, made equal to or larger than that of the first magnetic film near to the substrate surface, thus improving the magnetic isolation.

Magnetic recording medium and magnetic recording apparatus using the same

A perpendicular magnetic recording medium which has been improved to be suitable for high-density magnetic recording and a magnetic recording apparatus using the medium are provided. The magnetic back film of a dual-layer perpendicular recording medium is caused to be constituted by a plurality of layers, and a keeper layer for keeping perpendicular magnetization and layers and for improving the recording efficiency of a recording head are functionally separated from one another. Further, the magnetization orientations of the soft magnetic films excluding the keeper layer are defined to be in the circumferential direction of the disk, whereby the frequency of occurrence of noise is decreased.

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Fuchu, Japan

Yukio Honda