# US 7,744,966 B2 · Production process of perpendicular magnetic recording medium

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- Number: US 7,744,966 B2
- Document ID: US7744966B2
- Status: Granted
- Kind: B2
- Application number: 11/886,185
- Filed: 2006-03-16
- Published: 2008-08-21
- Granted: 2010-06-29
- Earliest claimed: 2005-03-17
- Assignees: Showa Denko K.K.
- Inventors: Masahiro Oka
- Web page: https://patentgrep.com/patent/US7744966B2

## CPC

- G11B 5/658: {containing oxygen, e.g. molecular oxygen or magnetic oxide}
- G11B 5/84: Processes or apparatus specially adapted for manufacturing record carriers
- G11B 5/8408: {protecting the magnetic layer}
- Y10T 428/11: Magnetic recording head
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A production process of magnetic recording media is provided in which, when using an oxide magnetic material as a perpendicular magnetic recording layer and forming a carbon protective layer using a plasma CVD method, stripping of the carbon protective layer and separation of a lubrication layer can be prevented, and satisfactory recording and reproduction characteristics can be obtained. In the production process of magnetic recording media, the magnetic recording media consists of, at least, a substrate 1 on which are provided a perpendicular magnetic recording layer and a carbon protective layer, in which the perpendicular magnetic recording layer consists of magnetic material containing a Co alloy and oxide material; the method includes a perpendicular magnetic recording layer formation process of forming the perpendicular magnetic recording layer on the substrate 1, a heating process of using a heating portion 28 to heat the substrate 1 on which the perpendicular magnetic recording layer has been formed, and a protective layer formation process of using a plasma CVD method to form a carbon protective layer on the substrate 1 on which the perpendicular magnetic recording layer has been formed.

## Claims

### Claim 1

A production process of a magnetic recording medium, which comprises a perpendicular magnetic recording layer and a carbon protective layer on a substrate, wherein the perpendicular magnetic recording layer is formed from a magnetic material containing a Co alloy and an oxide material, comprising:
a perpendicular magnetic recording layer formation process of forming the perpendicular magnetic recording layer on the substrate;
a heating process of heating the substrate on which has been formed the perpendicular magnetic recording layer; and,
a protective layer formation process of forming the carbon protective layer by the plasma CVD method on the substrate on which is formed the perpendicular magnetic recording layer,
wherein
in the perpendicular magnetic recording layer formation process, a temperature during formation of the perpendicular magnetic recording layer is less than 80° C,
in the protective layer formation process, a film deposition temperature during formation or the carbon protective layer is 80° C. or higher,
the perpendicular magnetic recording layer has a structure in which a nonmagnetic layer, consisting of an oxide material, surrounds a magnetic layer, consisting of a Co alloy, and
the oxide material is any one of, or is two or more among, SiO2, TiO, TiO2, ZrO2, Cr2O3 , CoO, Ta2O5, and Al2O3.