Perpendicular magnetic recording medium

Abstract

A perpendicular magnetic recording medium has a substrate, a soft magnetic underlayer formed on the substrate, arrayed soft magnetic dots formed on the soft magnetic underlayer, and a ferromagnetic recording layer formed on the soft magnetic dots and having magnetic anisotropy in a direction perpendicular to a surface of the substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-282439, filed Sep. 27, 2002, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a perpendicular magnetic recording medium capable of achieving high-density magnetic recording. [0004] 2. Description of the Related Art [0005] For performing high-density magnetic recording, it is necessary to reduce the size of magnetic domains, each of which is a recording unit of information. In the perpendicular magnetic recording medium that is generally used nowadays, information is recorded in a magnetic thin film containing magnetically disrupted magnetic grains. In order to reduce the size of the magnetic domains and to discriminate boundaries thereof for the high-density magnetic recording, it is necessary to reduce ...

AI Technical Summary

Benefits of technology

The present invention provides a perpendicular magnetic recording medium with high reliability and performance. The medium includes a substrate, a soft magnetic underlayer, arrayed soft magnetic dots, and a ferro-magnetic recording layer. The soft magnetic dots serve to attract magnetic flux even if the position of the magnetic pole of the head is deviated from the recording region, improving recording performance. The medium can also have a reduced flying height of the magnetic head and suppress fluctuation of magnetization transition extending over a ferromagnetic recording region, resulting in high-density magnetic recording.

Problems solved by technology

However, the problem of the thermal fluctuation inhibits the improvement in the recording density of the perpendicular magnetic recording medium.

As a result, it becomes problematic that the magnetic characteristics of the ferromagnetic recording layer are damaged; in particular, the magnitude and the direction of the perpendicular magnetic anisotropy are deteriorated.

However, it is difficult to lower the flying height in the patterned media, which has been irregularly processed, unlike the ordinary medium having a substantially flat surface.

However, it is difficult to locate the magnetic head accurately at the position of the individual ferromagnetic dot.

Where the position of the magnetic pole of the write head deviates greatly from the ferromagnetic dot, though a slight positional deviation is allowable, it is impossible to apply a recording magnetic field to a part of the ferromagnetic dot, with the result that effective recording magnetic field strength is lowered so as to render the recording efficiency poor.

Therefore, an appreciably large deviation between the magnetic head and the ferromagnetic dot is not allowable.

As described above, the problem that processing deteriorates the magnetic characteristics of the ferromagnetic recording layer was inherent in the conventional patterned media.

Also, the conventional patterned media was defective in that it was difficult to lower the flying height of the magnetic head, and that the allowable positional deviation between the write / read head and the ferromagnetic dot of the recording layer is small.

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