Hitachi, Ltd.

Sigeru Sano

Hideaki Tanaka

Yoshiki Kato

Masaki Ohura

Yoshihiko Miyake

Youichi Inomata

Hiroshi Yashiki

Kenichi Gomi

A magnetic disk includes a substrate, a magnetic layer, and a protective layer. At least one region of a surface of the magnetic disk has protrusions. A height of each of the protrusions is not less than 5 nm and not greater than 40 nm, and is within &plusmn;30% of an average height of the protrusions. A density of the protrusions is not less than 200/mm,and is not greater than 250,000/mm,. A width of a surface of each of the protrusions in a radial direction of the magnetic disk is not less than 0.1 &mgr;m and is not greater than 10 &mgr;m. The protrusions are discrete protrusions aligned in a spiral direction of the magnetic disk at a predetermined spacing in the radial direction of the magnetic disk. The at least one region of the surface of the magnetic disk includes flat areas between the protrusions. At least some of the flat areas extend continuously from an inner redius of the at least one region of the surface of the magnetic disk to an outer radius of t he at least one region of the surface of the magnetic disk.

Magnetic disk including protective layer having surface with protrusions, and substrate therefor

There is provided a magnetic disk apparatus comprising: at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate; a magnetic head which faces the magnetic disk in a rotating state with a micro gap and is supported by a slider; rotating means for rotating the magnetic disk; and a actuator for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein a plurality of protrusions each having a flat surface are formed in at least a region on the surface of the magnetic disk where a contact start/stop operation can be executed. According to the above magnetic disk apparatus, since the frictional force between the disk and the head is small and the flying height of the head can be reduced and the good floating stability is obtained, so that the excellent recording and reproducing characteristics are derived. Further, protrusions are formed on the protective layer of the magnetic disk and the protrusion shapes are changed in a accordance with a radial position of the magnetic disk depending on the flying height of the magnetic head. According to the above magnetic disk apparatus, since the change of spacing can be set smaller than the change of the flying height, high recording density can be achieved.

Magnetic disk including protective layer having surface with magnetic

Magnetic disk including protective layer having surface with protusions

Growing community of inventors

Fuji, Japan

Sigeru Sano