Hitachi, Ltd.

Other

Hitachi Maxell, Limited

Hitachi Cable, Inc.

Keikichi Ando

Norio Ohta

Motoyasu Terao

Yutaka Sugita

Makoto Miyamoto

Yasushi Miyauchi

Akemi Hirotsune

Yuzuru Hosoe

Yumiko Anzai

Tetsuya Nishida

Junko Ushiyama

Fumihiko Ishida

Tadashi Ikeda

Mitsuhide Miyamoto

Reiji Tamura

Yoshihiro Ikari

Hirofumi Sukeda

Toshimitsu Kaku

Yoshito Tsunoda

Nobuhiro Tokushuku

Kunikazu Ohnishi

Hiroyoshi Matsumura

Yukio Fukui

Tsuneo Suganuma

Kazuyuki Nagatsuma

Hiroshi Yasuoka

Takehiko Yorozu

Tamotsu Fuchioka

Tesuya Nishida

This invention relates to an information-recording medium that is used for recording information through radiation of energy beam. The information recording medium has a groove-shaped information recording track and is provided with a recording layer, one or more kinds of heat sink control layers and heat sink layers. A sum of film thickness of the more than one kind of recording layer is equal to or less than a step between information recording tracks, and a sum of film thickness of one or more kinds of heat sink control layers is more than a groove depth of the information recording track. With this configuration, no cross-erase is produced even if the information-recording medium is applied for a high density recording with the track pitch being 70% or less.

Information recording medium and information recording device

In an optical disk for high density recording, for preventing the deformation of recording tracks caused by stress which may develop between the substrate and the recording stacked film formed thereon, a stress-compensation layer having a metal element such as Ti or Cr as a main component is provided. The stress-compensation layer undergoes contraction (tensile stress) to compensate for compression stress which develops in the stacked film during cooling after the thermal expansion of the substrate surface that occurs at the end of film formation. The stress-compensation layer has a pillar-like structure which, starting from the lower face, reaches the upper face of the film.

Information recording medium and method for manufacturing information recording medium

An information recording medium having recording, reproducing, and rewriting characteristics better than those of prior art media. The media has a recording layer made of a material represented by the following formula: Ge Sb Te M , wherein 0.13&lE;x&lE;0.22, 0.20&lE;y&lE;0.32, 0.53&lE;z&lE;0.60, 0&lE;w&lE;0.06, x&plus;y&plus;z&equals;1, and M is any one of Na, Mg, Al, P, S, Cl, L, Ca, Sc, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ru, Rh, Cd, In, Sn, I, Cs, Ba, La, Hf, Ta, Re, Os, Ir, Hg, Tl, Pb, Th, U, Ag, Cr, W, Mo, Pt, Co, Ni, Pd, Si, Au, Cu, V, Mn, Fe, Ti and Bi.

Information recording medium

According to the present invention, a so-called overwrite operation which records new information while erasing existing information can be reliably performed in an information storage system such as optical disk system. In addition, whether the rewriting of recording has been properly done can be verified.

Method for recording and reproducing information using at least two

In a magnetic-field measuring apparatus having a Faraday rotation property, a medium having the Faraday rotation property includes at least one magnetic garnet thin film having a composition represented by a general formula of R.sub.3 (Fe.sub.5-x M.sub.x)O.sub.12 (where R is at least one element selected from a group consisting of La, Sm, Lu, Ca and Bi, or at least two elements selected from the group with Y being added thereto, M is at least one element selected from a group consisting of Ga, Ge, Al, Si, Sc, In and Cr, and a range of x is 0.ltoreq.x.ltoreq.1.5), and magnetized in a direction of light transmission, whereby an overall temperature characteristic of a ratio (4.pi.Ms/Ho) of a saturation flux density 4.pi.Ms to a collapse field Ho of a strip domain of the thin film is improved. The magnetic-field measuring apparatus offers a stable measurement of magnetic-field irrespective of a temperature change.

Optical magnetic-field measuring apparatus having improved temperature

The invention relates to a garnet film for an ion-implanted device characterized in that the quantity of Fe is increased and a predetermined quantity of Gd is added. The garnet film of the invention has a sufficiently high Curie temperature without sacrificing its other properties and hence is extremely suitable as a garnet film for an ion-implanted device.

Garnet film for ion-implanted magnetic bubble device

Herein disclosed is a magnetic garnet film for a magnetic bubble element, in which the temperature changing rate of a bubble collapse field is reduced by Gd and Ga and in which the operating characteristics of the bubbles are improved by La and Lu. The temperature coefficient of the bubble collapse field is -0.24 to 0%/.degree. C., and the operating characteristics are remarkably excellent, therefore, this garnet film is suitable for the small bubbles with a diameter smaller than or equal to 1 .mu.m.

Garnet film for magnetic bubble element

A magnetic garnet film for a magnetic bubble memory device in which parts of rare earth element and iron are replaced by predetermined quantities of Gd and Ge, respectively. The garnet film exhibits very small temperature-dependency of the bubble collapse field as well as high Curie temperature, whereby magnetic bubbles of very small diameter can be sustained and controlled with stability over a wide temperature range.

Garnet film for magnetic bubble device

A garnet film for a magnetic bubble domain device which comprises a predetermined quantity of Gd and a predetermined quantity of Ga. The garnet film has a temperature coefficient of not more than 0.2%/.degree.C. in respect of the bubble collapse field owing to the addition of Gd and Ga and is suitable for substaining small magnetic bubbles of a diameter of less than 2.5 .mu.m.

Film for a magnetic bubble domain device

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Musashino, Japan

Keikichi Ando