US4576700A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Perpendicular magnetic recording medium method for producing the same, and sputtering device
Assignee: Teijin Ltd
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Filing: 1983-02-16
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Granted: 1986-03-18
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Expires: 2003-02-16
Abstract
Abstract A magnetic recording medium conventionally utilizes the in-plane magnetization mode, but recently the perpendicular magnetization mode utilizing the perpendicular anisotropy of an hcp cobalt alloy layer, in which the C axis is oriented perpendicular to the layer surface, has been proposed. The known perpendicular magnetic recording medium is produced by means of RF sputtering and comprises a Permalloy layer, as layer of a low coercive-force material, between the nonmagnetic base and the hcp cobalt alloy layer. The perpendicular anisotropy attained by the present invention in very excellent and is superior to that of a perpendicular recording medium having no Permalloy layer because a Co-Ta alloy is used as the layer of a low coercive-force material.
Inventors
- 👤 Sadao Kadokura
- 👤 Kazuhiko Honjo
- 👤 Takashi Tomie
- 👤 Masahiko Naoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/851; G11B5/62; G11B5/64; G11B5/66; G11B5/672
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
187 words
A method for producing a perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, said layers comprising a first layer of low-coercive force material and a second layer of a cobalt alloy comprised of Co-Cr or Co-Cr and an additional elements of the group of W, Mo, Ru, Pt, As, Ni, Re and Ta, and which has a direction of easy magnetization in a direction perpendicular to the film surface, and wherein said layer of low-coercive force consists of a Co-Ta alloy which is mainly composed of cobalt and additionally tantalum, said method comprising the steps of: forming layer of said Co-Ta alloy by an opposed targets sputtering method by generating a magnetic field in a direction perpendicular to the surfaces of a pair of targets arranged opposite to one another within a sputtering device, and depositing material of said targets on the nonmagnetic base, which is located beside a space between said pair of targets and which faces said space; and forming said first and second cobalt alloy layers by means of the opposed targets. sputtering method.
Claim 2
Independent Claim
187 words
A method for producing a perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, said layers comprising a first layer of low-coercive force material and a second layer of a cobalt alloy comprised of Co-Cr or Co-Cr and an additional elements of the group of W, Mo, Ru, Pt, As, Ni, Re and Ta, and which has a direction of easy magnetization in a direction perpendicular to the film surface, and wherein said layer of low-coercive force consists of a Co-Ta alloy which is mainly composed of cobalt and additionally tantalum, said method comprising the steps of: forming layer of said Co-Ta alloy by an opposed targets sputtering method by generating a magnetic field in a direction perpendicular to the surfaces of a pair of targets arranged opposite to one another within a sputtering device, and depositing material of said targets on the nonmagnetic base, which is located beside a space between said pair of targets and which faces said space; and forming said first and second cobalt alloy layers by means of the opposed targets. sputtering method.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein said cobalt alloy layer is formed not later than ten hours after the formation of said layer of said Co-Ta alloy.
Claim 4
Dependent Claim
21 words
A method according to claim 2, wherein said cobalt alloy layer and said layer of said Co-Ta alloy are consecutively formed.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |