Ag Technology Co., Ltd.

Naohiko Ishimaru

Yuzo Murayama

Akihiko Tashiro

Kyoko Hyomi

Haruhiko Otsuka

A magnetic disk comprises a glass substrate and a magnetic layer formed on the glass substrate wherein the maximum deflection of a bent portion in the radial direction of the magnetic disk with respect to a reference length of 2 mm is 1,500 .ANG. or less in the entire region of a surface of the disk excluding annular areas having a width of 250 .mu.m which are respectively formed inwardly from annular lines at which chamfered portions formed at the inner and outer peripheries of the magnetic disk and the disk surface intersect.

Magnetic disk and a glass substrate for the magnetic disk

A magnetic disc having one or multiple undercoat layers, a continuous thin film magnetic layer or continuous thin film multiple magnetic layers, a protective layer and a lubricant layer sequentially laminated on a non-magnetic disc substrate, which has surface roughness on the surface of the magnetic disc, said surface roughness being such that when the surface roughness is measured by an atomic force microscope or a scanning tunnel microscope, the maximum peak height is from 150 .ANG. to 800 .ANG. based on the height giving the highest frequency in the height distribution of the surface roughness, and the depth (D.sub.0.5) at a bearing ratio of 0.5% from the highest point is from 80 .ANG. to 450 .ANG..

Growing community of inventors

Yokohama, Japan

Naohiko Ishimaru