IP Library Granted Patent US 6,855,416
Granted Patent B2
US 6,855,416 · App. 10/273,717 · Granted Feb 15, 2005

Thin film magnetic recording medium

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Quick Facts
Patent No.
US 6,855,416
App. No.
10/273,717
Granted
Feb 15, 2005
Kind
B2
Abstract

A thin film magnetic recording medium ( 30 ) is composed of an underlayer film ( 32 ), which is constituted by a nonmagnetic metal oxide film and formed on a nonmagnetic substrate ( 31 ), and a magnetic film ( 33 ) of Co system, which is formed on the underlayer film ( 32 ) through an oblique evaporation process, wherein each of the underlayer film and the magnetic film is laminated in order. Fine particles of the nonmagnetic metal oxide film grow isotropically in the underlayer film ( 32 ) constituted by the nonmagnetic metal oxide film and the underlayer film ( 32 ) is formed in a construction without having a clear grain boundary, which separates a aggregation of the fine particles.

Claims (5)

1. A thin film magnetic recording medium comprising: an underlayer film constituted by a nonmagnetic metal oxide film and formed on a nonmagnetic substrate with the underlayer film having a thickness within a range of 5 Å TO 300 Å; and a magnetic film of cobalt system formed on the underlayer film so that each is in direct contact with one another through an oblique evaporation process, with the thin film magnetic recording medium being further characterized in that fine particles of the nonmagnetic metal oxide film grow isotropically in the underlayer film constituted by the nonmagnetic metal oxide film and the underlayer film is formed in a construction without having a clear grain boundary separating an aggregation of the fine particles.

2. The thin film magnetic recording medium in accordance with claim 1 , wherein the underlayer film is formed by a sputtering method.

3. A thin film magnetic recording medium comprising: an underlayer film constituted by a nonmagnetic metal oxide film and formed on a nonmagnetic substrate wherein the underlayer film is a film of CoO; and a magnetic film of cobalt system formed on the underlayer film so that each is in direct contact with one another through an oblique evaporation process, with the thin film magnetic recording medium being further characterized in that fine particles of the nonmagnetic metal oxide film grow isotropically in the underlayer film constituted by the nonmagnetic metal oxide film and the underlayer film is formed in a construction without having a clear grain boundary separating an aggregation of the fine particles.

4. The thin film magnetic recording medium in accordance with claim 3 , wherein the underlayer film is formed by a sputtering method.

5. The thin film magnetic recording medium in accordance with claim 3 , wherein a film thickness of the underlayer film is within a range of 5 Å to 300 Å .

Assignments (5)
CORRECTIVE ASSIGNMENT TO CORRECT THE REMOVE PATENT NUMBERS 10342096;10671117; 10716375; 10716376;10795407;10795408; AND 10827591 PREVIOUSLY RECORDED AT REEL: 58314 FRAME: 657. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT. Recorded Feb 29, 2024
From: RAKUTEN, INC.
To: RAKUTEN GROUP, INC.
Reel/Frame 068066/0103 →
CHANGE OF NAME Recorded Dec 6, 2021
From: RAKUTEN, INC.
To: RAKUTEN GROUP, INC.
Reel/Frame 058314/0657 →
CHANGE OF ADDRESS Recorded Dec 17, 2015
From: RAKUTEN, INC.
To: RAKUTEN, INC.
Reel/Frame 037751/0006 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 11, 2012
From: JVC KENWOOD CORPORATION
To: RAKUTEN, INC.
Reel/Frame 028525/0760 →
MERGER Recorded Jul 4, 2012
From: VICTOR COMPANY OF JAPAN, LTD.
To: JVC KENWOOD CORPORATION
Reel/Frame 028489/0961 →