US4710434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optomagnetic recording medium
Assignee: Sony Corp
•
Filing: 1985-12-16
•
Granted: 1987-12-01
•
Expires: 2005-12-16
Abstract
Abstract An optomagnetic recording medium utilizing both rare earth metals and transition metals in the optomagnetic recording system. From 15 to 35 atomic % of the recording medium on the nonmagnetic base consists of one of the rare earth metals gadolinium (Gd), terbium (Tb) or dysprosium (Dy) with the balance being an alloyed mixture of iron (Fe), cobalt (Co) and germanium (Ge). The optomagnetic recording material of the present invention has an increased phase transition temperature without a rise in its Curie point, and provides satisfactory recording and erasing under temperature conditions up to near the Curie point.
Inventors
- 👤 Noboru Sato
- 👤 Kazutaka Habu
- 👤 Sanae Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:02
CPC Classifications
C; C22; C22C; C22C38/00; B; B82; B82Y; B82Y25/00; G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10591; H; H01; H01F; H01F10/00; H01F10/32; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
114 words
An optomagnetic recording medium comprising a non-magnetic base and a recording layer on said base having an overall composition of from 15 to 35 atomic % of at least one of the metals Gd, Tb, and Dy, with the remainder being composed of a mixture of Fe, Co, and Ge, said mixture containing 1 to 14 atomic % Ge, 5 to 10 atomic % Co and the balance essentially Fe, said recording layer being formed of alternately superposed layers in which some of said layers are enriched with at least one of said metals Gd, Tb, and Dy, and the others of said layers being enriched with said mixture of Fe, Co, and Ge.
Claim 2
Dependent Claim
114 words
An optomagnetic recording medium comprising a non-magnetic base and a recording layer on said base having an overall composition of from 15 to 35 atomic % of at least one of the metals Gd, Tb, and Dy, with the remainder being composed of a mixture of Fe, Co, and Ge, said mixture containing 1 to 14 atomic % Ge, 5 to 10 atomic % Co and the balance essentially Fe, said recording layer being formed of alternately superposed layers in which some of said layers are enriched with at least one of said metals Gd, Tb, and Dy, and the others of said layers being enriched with said mixture of Fe, Co, and Ge.
Claim 3
Dependent Claim
26 words
An optomagnetic recording medium according to claim 1 said recording layer having the overall analysis Tb 20 (Fe 90 Co 5 Ge 5 ) 80 .
Claim 4
Dependent Claim
29 words
An optomagnetic recording medium according to claim 1 wherein said recording layer has the overall composition represented by Tb 20 (Fe 85 Co 5 Ge 10 ) 80 .
Claim 5
Dependent Claim
27 words
An optomagnetic recording medium according to claim 1 wherein said recording layer has the overall analysis Tb 20 (Fe 85 Co 10 Ge 5 ) 80 .
Claim 6
Dependent Claim
27 words
An optomagnetic recording medium according to claim 1 wherein said magnetic layer has the overall composition (DyTb) 20 (Fe 90 Co 5 Ge 5 ) 80 .
Claim 7
Dependent Claim
28 words
An optomagnetic recording medium according to claim 1 wherein said recording layer has the overall analysis (Dy 20 ) (Fe 90 Co 5 Ge 5 ) 80 .
References Cited (Backward Citations)
US3965463A
Cited
US4293621A
Cited
US4347112A
Cited
JPS586542A
Cited
US4497870A
Cited
DE3317101A1
Cited
US4576699A
Cited
US4556291A
Cited
JPS60145541A
Cited
JPS60145543A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-30 | 1991-06-01 | 1991-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-30 | 1995-06-01 | 1995-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-30 | 1999-06-01 | 1999-12-01 | $7700.00 | Window Closed / Lapsed |