US4871614A
Expired / Lapsed
US
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Opto-magnetic recording medium having three exchange-coupled magnetic layers
Assignee: Canon Inc
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Filing: 1988-03-16
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Granted: 1989-10-03
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Expires: 2008-03-16
Abstract
Abstract An opto-magnetic recording medium includes: a substrate; a first magnetic layer formed on the substrate, the first magnetic layer having the following composition: [(Tb.sub.1-x Dy.sub.x)(Fe.sub.1-y CO.sub.y)].sub.1-z M.sub.z wherein 0≦x≦1, 0≦y≦0.3, and 0≦z≦0.2, and M is one element selected from the group consisting of Cr and Al; and two second magnetic layers respectively formed on the two surfaces of the first magnetic layer, each of the second magnetic layers having a lower coercive force and a higher Curie temperature than those of the first magnetic layer, and being exchange-coupled to the first magnetic layer, and each of the magnetic layers having the following composition: (GdFeCo).sub.1-w M.sub.w wherein 0≦w≦0.2, and M is one element selected from the group consisting of Cr or Al.
Inventors
- 👤 Tadashi Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:36
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10591; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
122 words
An opto-magnetic recording medium comprising: a substrate; a first magnetic layer formed on said substrate, said first magnetic layer having the following composition: [(Tb.sub.1-x Dy.sub.x)(Fe.sub.1-y Co.sub.y)].sub.1-z M.sub.z ` wherein 0≦x≦1, 0≦y≦0.3, and 0≦z≦0.2, and M is one element selected from the group consisting of Cr or Al; and two second magnetic layers respectively formed on the two surfaces of said first magnetic layer, each of said second magnetic layers having a lower coercive force and a higher Curie temperature than those of said first magnetic layer, and being exchange-coupled to said first magnetic layer, and each of said magnetic layers having the following composition: (GdFeCo).sub.1-w M.sub.w wherein 0≦w≦0.2, and M is one element selected from the group consisting of Cr or Al.
Claim 2
Dependent Claim
122 words
An opto-magnetic recording medium comprising: a substrate; a first magnetic layer formed on said substrate, said first magnetic layer having the following composition: [(Tb.sub.1-x Dy.sub.x)(Fe.sub.1-y Co.sub.y)].sub.1-z M.sub.z ` wherein 0≦x≦1, 0≦y≦0.3, and 0≦z≦0.2, and M is one element selected from the group consisting of Cr or Al; and two second magnetic layers respectively formed on the two surfaces of said first magnetic layer, each of said second magnetic layers having a lower coercive force and a higher Curie temperature than those of said first magnetic layer, and being exchange-coupled to said first magnetic layer, and each of said magnetic layers having the following composition: (GdFeCo).sub.1-w M.sub.w wherein 0≦w≦0.2, and M is one element selected from the group consisting of Cr or Al.
Claim 3
Dependent Claim
26 words
A medium according to claim 1, wherein said medium further comprises a protective layer formed on said magnetic layers on a side opposite to said substrate.
Claim 4
Dependent Claim
22 words
A medium according to claim 1, wherein said medium further comprises a reflection layer formed on one side of said magnetic layers.
Claim 5
Dependent Claim
24 words
A medium according to claim 1, wherein the Curie temperature of said first magnetic layer falls within a range of 90° to 120° C.
Claim 6
Dependent Claim
24 words
A medium according to claim 1, wherein the film thickness of said first magnetic layer falls within a range of 100 to 600 Å.
Claim 7
Dependent Claim
24 words
A medium according to claim 1, wherein the film thickness of said second magnetic layers falls within a range of 100 to 600 Å.
References Cited (Backward Citations)
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