EP0139474A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Magneto-optic memory element
Assignee: Sharp Corp
•
Filing: 1984-09-17
•
Granted: —
•
Expires: 2004-09-17
Abstract
Abstract A magneto-optic memory element inctades a transparent substrate, a first transparent nitride film, a GdTbFe recording layer, a second transparent nitride film, and a reflection film formed in this order. The first transparent nitride film has an index of refraction higher than that of the second transparent nitride film. In a preferred form, the first transparent nitride film is a SiN film having the index of refraction of about 2.0, and the second transparent nitride film is an AIN film having the index of refraction of about 1.8 to 1.9.
Inventors
- 👤 Akira Takahashi
- 👤 Yoshiteru Murakami
- 👤 Junji Hirokane
- 👤 Hiroyuki Katayama
- 👤 Kenji Ohta
- 👤 Hideyoshi Yamaoka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 23:48
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10593; H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; H01F10/12; H01F10/126; H01F10/14; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
97 words
A magneto-optic memory element comprising: a transparent substrate; a first transparent nitride dielectric layer formed on said transparent substrate, said first transparent nitride dielectric layer having a first index of refraction; an alloy thi-n-film recording layer including rare earth element and transition metal formed on said first transparent nitride dielectric layer; a second transparent nitride dielectric layer formed on said alloy thin-film recording layer, said second transparent nitride dielectric layer having a second index of refraction which is smaller than said first index of refraction; and a reflection layer formed on said second transparent nitride dielectric layer.
Claim 2
Dependent Claim
97 words
A magneto-optic memory element comprising: a transparent substrate; a first transparent nitride dielectric layer formed on said transparent substrate, said first transparent nitride dielectric layer having a first index of refraction; an alloy thi-n-film recording layer including rare earth element and transition metal formed on said first transparent nitride dielectric layer; a second transparent nitride dielectric layer formed on said alloy thin-film recording layer, said second transparent nitride dielectric layer having a second index of refraction which is smaller than said first index of refraction; and a reflection layer formed on said second transparent nitride dielectric layer.
Claim 3
Dependent Claim
27 words
The magneto-optic memory element of claim 1, wherein said first index of refraction is about 2.0, and said second index of refraction is about 1.8 to 1.9.
Claim 4
Dependent Claim
22 words
The magneto-optic memory element of claim 2, wherein said alloy thin-film recording layer is a GdTbFe alloy thin-film of 35 nm thick.
Claim 5
Dependent Claim
39 words
The magneto-optic memory element of claim 2, wherein said first transparent nitride dielectric layer is a SiN film of about 90 nm thick, and said second transparent nitride dielectric layer is an AIN film of about' 40 nm thick.
Claim 6
Dependent Claim
47 words
The magneto-optic memory element of claim 1, wherein said first and second transparent nitride dielectric layers are formed by a reactive sputtering method, and wherein the sputtering condition is controlled so as to differ the index of refraction between said first and second transparent nitride dielectric layers.
Claim 7
Dependent Claim
59 words
The magneto-optic memory element of claim 5, wherein said first transparent nitride dielectric layer is an AIN film of about 90 nm thick having said first index of refraction of about 2.0, and said second transparent nitride dielectric layer is an AIN film of about 40 nm thick having said second index of refraction of about 1.8 to 1.9.
Claim 8
Dependent Claim
37 words
The magneto-optic memory element of claim 5, wherein a gas pressure at which said first transparent nitride dielectric layer is formed is lower than a gas pressure at which said second transparent nitride dielectric layer is formed.
Claim 9
Dependent Claim
65 words
The magneto-optic memory element of claim 5, wherein said first transparent nitride dielectric layer is a Si 3 N 4 film of about 90 nm thick having said first index of refraction of about 2.0, and said second transparent nitride dielectric layer is a Si 3 N 4 film of about 40 nm thick having said second index of refraction of about 1.8 to 1.9.
Claim 10
Dependent Claim
19 words
The magneto-optic memory element of claim 6, wherein said alloy thin-film recording layer is a GdTbFe alloy thin-film layer.
Claim 11
Dependent Claim
19 words
The magneto-optic memory element of claim 8, wherein said alloy thin-film recording layer is a GdTbFe alloy thin-film layer.
Claim 12
Dependent Claim
20 words
A magneto-optic memory medium comprising an amorphous alloy thin-film recording layer sandwiched between a pair of transparent nitride dielectric films.
Claim 13
Dependent Claim
20 words
A magneto-optic memory medium comprising an amorphous alloy thin-film recording layer sandwiched between a pair of transparent nitride dielectric films.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.