1. Field of the Invention
This invention relates to a magnetic disk and magnetic disk unit provided with this disk for recording and reproducing data and programs by means of a magnetic head mounted on a floating head slider.
2. Description of Related Art
Computer systems, for example, utilize a hard disk unit as the magnetic disk unit. The magnetic disk housed inside this hard disk unit is covered with a magnetic film on both surfaces and data is recorded or reproduced in a track configuration on this magnetic film by means of a magnetic head mounted on a floating head slider "above" both sides of the magnetic disk.
Because such a magnetic disk is covered with a magnetic film on both entire surfaces and magnetized in the longitudinal magnetic recording direction namely in the direction horizontal to a magnetic film, the width of a guard band provided between adjacent data tracks should be inevitably relatively wide in order to suppress crosstalk from adjacent data tracks. As a result, the width of a track pitch cannot be narrow, and a small-sized hard disk with large recording capacity has not been realized. This is a problem.
To solve this problem, a vertical magnetic recording magnetic disk namely, a magnetic disk magnetized in the direction perpendicular to the magnetic film, has been proposed. The recording density of a magnetic disk is determined by the product of line density and track density. A recording signal with short wavelength may be employed to increase the line density, this means that magnetization reversal width for signal recording is reduced,
Generally in the comparison of a vertical magnetic recording system with a longitudinal magnetic recording system, it is said that the magnetization reversal width is smaller for a vertical magnetization recording system than for a longitudinal magnetization recording system. The difference is attributed to the fact that the magnetization reversal region in a longitudinal magnetic recording system is composed of the same polar magnetic poles, on the other hand, the magnetization reversal region in a vertical magnetic recording system is composed of the different magnetic poles. Therefore, a guard band between data tracks of a magnetic disk of the vertical magnetic recording system can be relatively narrow, and a small-sized hard disk unit with large recording capacity can be realized.
According to the above-mentioned magnetic disk of the vertical magnetic recording system, the high recording density can be realized.
However in the vertical magnetic recording system, because the spacing loss due to the distance between a magnetic disk and a magnetic head is serious, it is necessary to reduce the lift amount between a magnetic disk and a head slider as small as possible.