Perpendicular magnetic recording medium and method of manufacturing the same

Abstract

A vertical magnetic recording disc (100) includes a base (10), a magnetic recording layer (22), and a medium protection layer (26). The magnetic recording layer (22) is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer (26) contains nitrogen (N) atoms and carbon (C) atoms with a number ratio (N / C) in a range from 0.050 to 0.150. In a Raman spectrum obtained by exciting the medium protection layer (26) by argon ion laser light of wavelength 514.5 nm, from which a fluorescence is removed, the peak ratio Dh / Gh is in a range from 0.70 to 0.95, when a D peak Dh appearing in the vicinity of 1350 cm−1 is separated from G peak Gh appearing in the vicinity of 1520 cm−1 by the Gauss function.

Description

TECHNICAL FIELD[0001]The present invention relates to a perpendicular magnetic recording medium that is loaded on, for example, an HDD (hard disk drive) using a perpendicular magnetic recording system and also relates to a method of manufacturing the medium.BACKGROUND ART[0002]In accordance with the recent increasing storage capacity in information processing, various types of information recording technologies have been developed. In particular, the surface recording density of an HDD using a magnetic recording technology has been increasing at an annual rate of about 100%. Recently, 2.5-inch-diameter perpendicular magnetic recording disks used in HDDs and the like also have been required to have an information recording capacity of larger than 100 GB per disk. In order to satisfy such a requirement, it is necessary to achieve an information recoding density of higher than 150 Gbits per square inch.[0003]In order to achieve a high recording density in a perpendicular magnetic recor...

AI Technical Summary

Benefits of technology

The present invention relates to a perpendicular magnetic recording medium and a method of manufacturing it. The invention aims to solve the problem of thermal fluctuation in recorded signals caused by the superparamagnetic phenomenon in conventional in-plane magnetic recording systems. The perpendicular magnetic recording system has the advantage of suppressing thermal fluctuation, but the size reduction of crystalline magnetic particles constituting the magnetic recording layer has led to a decrease in thermal stability of recorded signals. The invention proposes a medium-protecting layer for protecting the surface of the magnetic recording layer from being damaged when the magnetic head crashes with the perpendicular magnetic recording disk. The medium-protecting layer forms a carbon overcoat (COC) with high hardness due to a carbon coating. The invention also discusses a technology for producing a diamond-like bond protection film and enhancing durability of the medium-protecting layer. Additionally, the invention proposes a lubrication layer for protecting the medium-protecting layer and the magnetic head from the crash of the magnetic head.

Problems solved by technology

However, in a case of a magnetic disk of a conventionally commercialized in-plane magnetic recording system (also called a longitudinal magnetic recording system or a horizontal magnetic recording system), as a result of the progress in the size reduction of crystalline magnetic particles, thermal stability of recorded signals is deteriorated by the superparamagnetic phenomenon.

However, since the magnetic flux emerging from a single-pole end is prone to promptly return to a return magnetic pole on the opposite side, a magnetic field with a sufficient intensity cannot be applied to the magnetic recording layer by using only the single-pole-type perpendicular head.

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