US4883711A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: HGST Japan Ltd
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Filing: 1987-12-15
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Granted: 1989-11-28
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Expires: 2007-12-15
Abstract
Abstract A magnetic recording medium in which a non-magnetic intermediate layer made of an alloy substantially composed of at least one element selected from the group consisting of Zr, Hf, Ta, Ti and Nb is disposed between a magnetic layer formed on a substrate and a non-magnetic overcoat layer formed on the magnetic layer. Since the impact shock resistance and the vibration resistance of the magnetic recording medium can be improved and the head-medium spacing of the magnetic disc apparatus can be decreased extremely by disposing the non-magnetic intermediate layer, it can provide a increase in the recording density, particularly, in a thin film type magnetic recording medium using a metallic magnetic thin film or metal oxide thin film as the magnetic layer. It can also improve the corrosion resistance in the case of a metallic magnetic thin film type medium.
Inventors
- 👤 Yoshihiro Shiroishi
- 👤 Sadao Hishiyama
- 👤 Hiroyuki Suzuki
- 👤 Tomoyuki Ohno
- 👤 Yoshibumi Matsuda
- 👤 Kazumasa Takagi
- 👤 Norikazu Tsumita
- 👤 Yasushi Kitazaki
- 👤 Masaki Ohura
- 👤 Sadanori Nagaike
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:49
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/736; G11B5/7368; G11B5/7373; G11B5/72; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
90 words
A magnetic recording medium having a magnetic layer over a substrate , a non-magnetic overcoat layer over said magnetic layer and a non-magnetic intermediate layer disposed between said magnetic layer and said non-magnetic overcoat layer, wherein said non-magnetic intermediate layer is made of an alloy substantially composed of at least one element selected from the group consisting of Zr, Hf and Ti and contains at least one element selected from the group consisting of Pt, Pd, Rh, Ir, Ru and Os in an amount from 0.01 to 1.0 at %.
Claim 2
Dependent Claim
90 words
A magnetic recording medium having a magnetic layer over a substrate , a non-magnetic overcoat layer over said magnetic layer and a non-magnetic intermediate layer disposed between said magnetic layer and said non-magnetic overcoat layer, wherein said non-magnetic intermediate layer is made of an alloy substantially composed of at least one element selected from the group consisting of Zr, Hf and Ti and contains at least one element selected from the group consisting of Pt, Pd, Rh, Ir, Ru and Os in an amount from 0.01 to 1.0 at %.
Claim 3
Dependent Claim
67 words
A magnetic recording medium as defined in claim 1, wherein an underlayer comprising at least one element selected from the group consisting of Cr, Mo, W, Ti, C, Ge and Si or a non-magnetic alloy substantially composed of one of Cr, Mo, W, Ti, C, Ge and Si with a film thickness of from 100 to 5000 Å is disposed between the magnetic layer and the substrate.
Claim 4
Dependent Claim
23 words
A magnetic recording medium as defined in claim 1, wherein said magnetic layer comprises a metallic magnetic thin film substantially composed of Co.
Claim 5
Dependent Claim
25 words
A magnetic recording medium as defined in claim 3, wherein the magnetic layer is a metallic magnetic thin film substantially composed of CoNi and Zr.
Claim 6
Dependent Claim
43 words
A magnetic recording medium as defined in claim 4, wherein the metallic magnetic thin film contains Ni by from 30 to 48 at % based on Co, and Zr by from 3 to 12 at % based on the total amount of CoNi.
Claim 7
Dependent Claim
28 words
A magnetic recording medium as defined in claim 1, wherein said non-magnetic intermediate layer and said non-magnetic overcoat layer have a total thickness from 100 to 1000 Å.
Claim 8
Dependent Claim
23 words
A magnetic recording medium as defined in claim 6, wherein said non-magnetic overcoat layer has a greater thickness than said non-magnetic intermediate layer.
Claim 9
Dependent Claim
19 words
A magnetic recording medium as defined in claim 1, wherein said non-magnetic intermediate layer comprises a plurality of layers.
Claim 10
Dependent Claim
22 words
A magnetic recording medium as defined in claim 1, wherein said non-magnetic intermediate layer has a thickness from 50 to 200 Å.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |