US4666788A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Perpendicular magnetic recording medium, method for producing the same, and sputtering device
Assignee: Teijin Ltd
•
Filing: 1986-01-15
•
Granted: 1987-05-19
•
Expires: 2006-01-15
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 is 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
2026-11-01 13:49
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; G11B5/84; G11B5/851; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
A perpendicular magnetic recording medium comprising: a non-magnetic base; a first magnetic layer of low-coercive force material formed on said non-magnetic base, said first magnetic layer consisting essentially of an alloy which is mainly composed of cobalt and additionally of tantalum; and a second magnetic cobalt alloy layer having a composition different from said first magnetic layer and having a direction of easy magnetization in a direction perpendicular to the surface of said recording medium formed on said first magnetic layer.
Claim 2
Dependent Claim
81 words
A perpendicular magnetic recording medium comprising: a non-magnetic base; a first magnetic layer of low-coercive force material formed on said non-magnetic base, said first magnetic layer consisting essentially of an alloy which is mainly composed of cobalt and additionally of tantalum; and a second magnetic cobalt alloy layer having a composition different from said first magnetic layer and having a direction of easy magnetization in a direction perpendicular to the surface of said recording medium formed on said first magnetic layer.
Claim 3
Dependent Claim
24 words
A perpendicular magnetic recording medium according to claim 1, wherein a Ta concentration of said first magnetic layer is at least 6.4 atomic %.
Claim 4
Dependent Claim
16 words
A perpendicular magnetic recording medium according to claim 2, wherein said first magnetic layer is amorphous.
Claim 5
Dependent Claim
19 words
A perpendicular magnetic recording medium according to claim 1, wherein said second magnetic cobalt alloy layer additionally contains Cr.
Claim 6
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 1, wherein said second magnetic cobalt alloy layer additionally contains Cr and Ta.
Claim 7
Dependent Claim
45 words
A perpendicular magnetic recording medium according to claim 5, wherein the Ta concentration of said second magnetic cobalt alloy layer is from 2 atomic % to 10 atomic %, with the proviso that sum of the Cr-Ta concentrations is 27 atomic % at the highest.
Claim 8
Dependent Claim
16 words
A perpendicular nonmagnetic according to claim 1 wherein said nonmagnetic base is a polyethylene terephtalate film.
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) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |