Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Noriyuki Takeo

Takashi Naito

Hiroki Yamamoto

Ken Takahashi

Takashi Namekawa

Akira Kato

Yasutaka Suzuki

Youichi Inomata

Masatomo Terakado

Kiyoshi Akamatsu

Masahiro Watanabe

A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% of less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Glass substrate for a magnetic disk, a magnetic disk which can be formed with a stable texture and a magnetic disk device

In accordance with the present invention, a glass substrate of a disk for recording information, containing oxides of rare earth elements and fine particles dispersed therein, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided. The glass substrate of the disk for recording information having preferable mechanical characteristics, as well as superior chemical stability, thermal stability, flatness, and transparency is provided, and a disk for recording information and a disk apparatus for recording information using the glass substrate of the disk are provided.

Glass substrate of disk for recording information, a disk for recording information, and a disk device for recording information

A glass substrate for a magnetic disk contains a transition metal. The substrate, which is subjected to formation of zone texturing by irradiating the substrate with a laser beam, has a high mechanical strength even if it is not chemically strengthened. The glass substrate contains a transition metal element and has a transmittance of 10% or less for light in a wavelength range of 300 to 2000 nm. The surface roughness of an information recording surface portion thereof is 2.0 nm or less. In addition to a transition metal element, the glass substrate may include a rare earth metal element.

Glass substrate for a magnetic disk, a magnetic disk which can be formed with a stable texture

Glass substrate of disk for recording information, a disk for recording

Growing community of inventors

Yamakita-machi, Japan

Noriyuki Takeo