Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Tokuda Seisakusho, Ltd.

Reiji Nishikawa

Masayuki Sagoi

Toshiyuki Suzuki

Takashi Hikosaka

Atsuko Iida

Masaki Katsura

Norio Ozawa

Tatsuo Fujiwara

Toshimitsu Asano

Hirosi Ohdaira

Hidetaka Jyo

Masayuki Kanamaru

Kazuyoshi Yamamori

Shozo Satoyama

Yoshinori Ito

A thin film type longitudinal magnetic recording medium is manufactured by forming a magnetic layer of Co.sub.1-x-y Pt.sub.x Cr.sub.y, (0.15&lt;x.ltoreq.0.35; 0&lt;y.ltoreq.0.15), on a substrate. The magnetic layer is formed by sputtering under an inert gas atmosphere containing 0.1 to 15% by volume of at least one of N.sub.2 and O.sub.2.

Magnetic recording medium and method of manufacturing same

Disclosed is an optical recording medium comprising a transparent substrate having a tracking line formed therein, and a recording layer formed on that surface of the substrate in which is formed the tracking line. The recording layer consists of a low oxide of nickel. Also disclosed is an optical recording medium comprising a transparent substrate consisting of a thermoplastic resin, a thermosetting resin layer formed on each surface of the substrate, a patterned photoresist layer, said patterned photoresist layer being formed on one of the thermosetting resin layer, and a recording layer formed to cover the exposed portion of the thermosetting resin layer and the patterned photoresist layer.

Optical recording medium

A perpendicular magnetic recording floppy disk comprises a flexible plastic film substrate, a first magnetic recording layer formed on one side of the plastic film substrate and having an axis of easy magnetization in a direction perpendicular to the one side of the plastic film substrate, and a second magnetic recording layer formed on the other side of the plastic film substrate and having an axis of easy magnetization in a direction perpendicular to the above-mentioned other side of the plastic film substrate. The second magnetic recording layer has a thickness greater than a thickness of the first magnetic recording layer.

Perpendicular magnetic recording floppy disk

A method of manufacturing a perpendicular magnetic recording floppy disk is disclosed. A first magnetic recording layer is formed by sputtering a perpendicularly magnetizable material on one side of a plastic film substrate. A second magnetic recording layer is formed by sputtering the perpendicularly magnetizable material on the other side of the plastic film substrate after forming the first magnetic recording layer. The second magnetic recording layer has a thickness greater than that of the first magnetic recording layer, when a curl of the first magnetic recording layer on the plastic film substrate, resulting from forming the first magnetic recording layer on the plastic film substrate, is to the outside. On the other hand, the second magnetic recording layer has a thickness lower than that of the first magnetic recording layer, when a curl of the first magnetic recording layer on the plastic film substrate is to the inside.

Method of manufacturing perpendicular magnetic recording floppy disk

In a magnetic recording disk of a double-sided data recording type according to a perpendicular magnetic recording technique of the invention, recording layers having different film thicknesses are formed on two surfaces of a base layer. The film thickness of one magnetic recording layer is set to be larger than the film thickness of the other magnetic recording layer, thereby preventing a curl phenomenon. In addition, a coercive force of the thicker recording layer is set to be smaller than that of the thinner layer. Thus, differences in a reproduction output voltage and an optimal recording current between the two recording layers of the disk due to a film thickness difference can be compensated for.

Magnetic recording medium

In a magnetic recording disk of a double-sided recording type according to a perpendicular magnetic recording technique of the invention, recording layers having different film thicknesses are formed on two surfaces of a base layer. The film thickness of one magnetic recording layer is set to be larger than the film thickness of the other magnetic recording layer. Thus, a curl phenomenon can be prevented. In addition, a coercive force of the thicker recording layer is set to be higher than that of the thinner recording layer. A difference in a perpendicular recording density between the two recording layers due to a difference in the film thickness thereof can be compensated for.

A perpendicular magnetic-recording medium wherein an amorphous alloy layer of nickel and phosphorus is formed on a disc substrate; the surface of the alloy layer is smoothed with high precision; and a ferromagnetic Co-based perpendicular magnetic-recording layer is formed on the smoothed surface of the alloy layer.

Perpendicular magnetic-recording medium

There is disclosed a magnetron sputtering apparatus including a sputtering chamber, a substrate and target disposed within the sputtering chamber to form a desired space therebetween, device for applying a voltage between the substrate and target, and device for producing a magnetic field; and the apparatus comprises the magnetic field-producing device adapted to excite a magnetic field so that the direction of the magnetic field may be inverted on the magnetic symmetry axis within the space. The magnetron sputtering apparatus of the present invention can form metal films having no crack without heating of the substrate and also form a magnetic recording film layer having an increased coercive force perpendicular to the surface of the film.

Magnetron sputtering apparatus

A magnetic recording medium for perpendicular magnetic recording comprises a low coercive force material, and a magnetic recording layer which is formed on the low coercive force layer and has magnetic anisotropy perpendicular to the surface of said low coercive force layer. The magnetic recording layer is of 0.3 .mu.m or less in thickness.

Growing community of inventors

Yokohama, Japan

Reiji Nishikawa