Magnetic recording medium

• US 4,761,334 A
• Filed: 07/01/1985
• Issued: 08/02/1988
• Est. Priority Date: 09/21/1984
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sagoi, Masayuki, Sekine, Kunio, Tanaka, Yoichiro, Kawashima, Noritsugu
• Primary Examiner(s): Thibodeau, Paul J.
• Application Number:
  US06/750,271
• Time in Patent Office: 1,128 Days
• Field of Search: 428/694, 428/695, 428/900, 428/332, 428/698, 427/131
• US Class Current: 428/332
• CPC Class Codes: G11B 5/64 comprising only the magnetic material without bonding agent
• CPC Class Codes: G11B 5/71 characterised by the lubricant
• CPC Class Codes: G11B 5/7253 Fluorocarbon lubricant
• CPC Class Codes: G11B 5/7262 Inorganic protective coating
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A magnetic recording medium in which a silicon nitride film is formed on a magnetic recording layer having an axis of easy magnetization in the direction essentially perpendicular to its own layer surface. The magnetic recording layer is a metallic magnetic film such as a Co-Cr containing alloy. The silicon nitride film is preferably in a state in which the number of nitrogen atoms is less than four thirds of the number of silicon atoms. A lubricant layer such as a layer of fluorocarbon can be formed on the silicon nitride film.

Claims

1. A magnetic recording medium comprising:

a substrate;

at least one magnetic recording layer formed on a surface of the substrate, having an axis of easy magnetization in a direction essentially perpendicular to a surface of the layer thereof; and

a silicon nitrode film formed on the magnetic recording layer, the number of nitrogen atoms in the silicon nitride film being less than four thirds of the number of silicon atoms therein.

2. A magnetic recording medium according to claim 1, wherein the silicon nitride film has a composition of Si₃ N_4-x, where x is more than zero and less than two.

3. A magnetic recording medium according to claim 1, further comprising a lubricant layer formed on the silicon nitride film.

4. A magnetic recording medium according to claim 3, wherein the lubricant layer comprises a fluorocarbon-containing lubricant.

5. A magnetic recording medium according to claim 1, wherein the magnetic recording layer comprises a metallic thin film.

6. A magnetic recording medium according to claim 5, wherein the magnetic recording layer is a Co-Cr containing alloy.

7. A magnetic recording medium according to claim 1, further comprising a second magnetic recording layer formed on a second surface of the substrate, and a second silicon nitride film formed on said second magnetic recording layer, the number of nitrogen atoms in the second silicon nitride layer being less than four thirds of the number of silicon atoms therein.

8. A magnetic recording medium for use with a magnetic recording system that records using a magnetic head, said medium comprising:

a substrate;

at least one magnetic recording layer formed of an alloy which as a Cr component overlying said substrate; and

a silicon nitrde film formed as a top layer of said magnetic recording medium, and adapted to contact said magnetic head.

9. A medium as in claim 8 wherein said silicon nitride layer is formed directly on said magnetic recording layer.

10. A medium as in claim 9 wherein said alloy is an alloy of Co-Cr.

11. A medium according to claim 10 wherein the thickness of said silicon nitride film is between 20 Å

and 500 Å

.

12. A medium according to claim 10 wherein the thickness of said silicon nitride film is between 50 Å

and 400 Å

.

13. A medium as in claim 8 further comprising a ferromagnetic layer underlying said silicon nitride film and overlying said substrate and underlying said magnetic recording layer, against a bottom surface thereof.

14. A medium according to claim 10 further comprising a second magnetic recording layer formed on a second surface of said substrate, and a second silicon nitride film formed on said second magnetic recording layer.

15. A magnetic recording medium, comprising:

a substrate;

at least one magnetic recording layer of a Co-Cr containing alloy formed on a surface of the substrate, having a perpendicular magnetic anisotropy;

a silicon nitrode film formed on the magnetic recording layer; and

a lubricant layer formed directly on the silicon nitride film, said lubricant layer being a top layer of said magnetic recording medium adapted to contact a recording head.

16. A magnetic recording medium according to claim 15, wherein the lubricant layer comprises a fluorocarbon-containing lubricant.

17. A magnetic recording medium according to claim 15 , wherein the thickness of the silicon nitrode film is between 150 Å

and 250 Å

, and the thickness of the lubricant layer is between 30 Å and

50 Å

.

18. A magnetic recording medium according to claim 15, further comprising a second magnetic recording layer formed on a second surface of said substrate, a second silicon nitride layer formed on said second magnetic recording layer and a second lubricant layer formed on said second silicon nitride layer.

19. A medium according to claim 15 wherein said silicon nitride film is formed directly on the magnetic recording layer,

20. A medium according to claim 19 wherein the silicon nitride film and lubricant layer have thicknesses between 50 Å

and 400 Å

.

21. A magnetic recording medium, comprising:

a substrate;

a magnetic recording layer formed on a surface of the substrate, said magnetic recording layer being a Co-Cr containing alloy; and

a silicon nitride film means, including a silicon nitride'"'"' film formed directly on said Co-Cr alloy as a top layer of said magnetic recording medium.

22. A medium as in claim 21 wherein said silicon nitride film means includes a lubricant layer on said silicon nitride film.