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US4608142A
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Method of manufacturing magneto-optic recording film
Assignee: Nippon Sheet Glass Co Ltd
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Filing: 1984-11-15
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Granted: 1986-08-26
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Expires: 2004-11-15
Abstract
Abstract In a method of manufacturing a magneto-optic recording film wherein a vertically magnetized film of a Bi-substituted rare-earth iron garnet is formed on a substrate, a target consisting of an oxide containing at least Bi atoms, Fe atoms and rare-earth element atoms is sputtered, and the atoms constituting the oxide which are released from the target by sputtering are deposited on the substrate which is held at a temperature of 700° C. or lower, thereby forming the vertically magnetized film consisting of the Bi-substituted rare-earth iron garnet. With this method, a vertically magnetized film of a Bi-substituted rare-earth iron garnet having a large Bi substitution amount x, a very large Faraday rotation angle θ F , a sufficiently large coercive force H c and a sufficiently small absorption coefficient α can be manufactured, so that a magneto-optic recording film having excellent magneto-optic recording characteristics can be manufactured. In addition, since the material of the substrate on which a magneto-optic recording film is formed can be selected from various materials, the method is extremely advantageous from the manufacturing point of view.
Inventors
- 👤 Manabu Gomi
- 👤 Masanori Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:21
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10591; C; C23; C23C; C23C14/00; C23C14/06; C23C14/08; C23C14/22; C23C14/34; C23C14/3407; C23C14/3414; G03; G03G; G03G5/00; G03G5/16; H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; H01F10/18; H01F10/20; H01F10/24; H01F10/245
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
89 words
A method of manufacturing a magneto-optic recording film wherein a vertically magnetized film of a Bi-substituted rare-earth iron garnet is formed on a substrate, characterized in that a target consisting of an oxide containing at least Bi atoms, Fe atoms and rare-earth element atoms is sputtered, and the atoms constituting the oxide which are released from the target by sputtering are deposited on the substrate which is held at a temperature of 700° C. or lower, thereby forming the vertically magnetized film consisting of the Bi-substituted rare-earth iron garnet.
Claim 2
Independent Claim
89 words
A method of manufacturing a magneto-optic recording film wherein a vertically magnetized film of a Bi-substituted rare-earth iron garnet is formed on a substrate, characterized in that a target consisting of an oxide containing at least Bi atoms, Fe atoms and rare-earth element atoms is sputtered, and the atoms constituting the oxide which are released from the target by sputtering are deposited on the substrate which is held at a temperature of 700° C. or lower, thereby forming the vertically magnetized film consisting of the Bi-substituted rare-earth iron garnet.
Claim 3
Dependent Claim
71 words
A method according to claim 1, wherein the target has a formula (Bi 2 O 3 ) x (R 2 O 3 ) y (Fe 2 O 3 ) z (M 2 O 3 ) u {wherein R is a rare-earth element, M is an atom having a valence of 3 or a group of atoms having a valence equivalent to a valence of 3, and 0<x≦3/2, 0<y≦3/2, 0<z<5/2, and 0≦u≦5/2}.
Claim 4
Dependent Claim
71 words
A method according to claim 1, wherein the target has a formula (Bi 2 O 3 ) x (R 2 O 3 ) y (Fe 2 O 3 ) z (M 2 O 3 ) u {wherein R is a rare-earth element, M is an atom having a valence of 3 or a group of atoms having a valence equivalent to a valence of 3, and 0<y≦3/2, 1<(2/3)x+y≦3/2, 3/2<z≦5/2, and z+u=5/2}.
Claim 5
Dependent Claim
63 words
A method according to claim 1, wherein the target is a sintered ceramics consisting of coexisting multiple phases having a formula Bi a R b (Fe, M) 5 O 12 {wherein R is a rare-earth element, M is an atom having a valence of 3 or a group of atoms having a valence equivalent to a valence of 3, and 1.5<a≦9/2 and 2<(2/3)a+b≦3}.
Claim 6
Independent Claim
61 words
A method according to any one of claims 2 to 4, wherein the atom having a valence of 3 or the group of atoms having a valence equivalent to a valence of 3 represented by M is selected from the group consisting of Al 3+ , Ga 3+ , Sc 3+ , Tl 3+ , and (Co 2+ +Ti 4+ ).
Claim 7
Independent Claim
23 words
A method according to any one of claims 1 to 5, wherein the substrate is a (111) oriented monocrystalline gadolinium galium garnet substrate.
Claim 8
Dependent Claim
15 words
A method according to claim 6, wherein the substrate temperature is 350° to 700° C.
Claim 9
Dependent Claim
39 words
A method according to claim 1, wherein an amorphous thin film which can be converted into a Bi-substituted rare-earth iron garnet by iron garnet by crystallization is formed by sputtering, and the amorphous thin film is crystallized by annealing.
Claim 10
Dependent Claim
13 words
A method according to claim 8, wherein the substrate is a glass substrate.
Claim 11
Dependent Claim
15 words
A method according to claim 8, wherein the substrate temperature is 300° to 500° C.
Claim 12
Dependent Claim
15 words
A method according to claim 8, wherein the substrate temperature is 400° to 450° C.
Claim 13
Dependent Claim
15 words
A method according to claim 8, wherein the annealing temperature is 500° to 900° C.
Claim 14
Dependent Claim
59 words
A method according to claim 8, wherein an amorphous thin film which can be converted into a Bi-substituted rare-earth iron garnet by crystallization is formed on the substrate by sputtering, a protective film for preventing vaporization of Bi is formed on the amorphous thin film, and annealing is performed so as to crystallize the amorphous Bi-substitued rare-earth iron garnet.
Claim 15
Dependent Claim
49 words
A method according to claim 13, wherein the protective film is one member selected from the group consisting of an SiO 2 film, a ZnO film, a TiO 2 film, a CeO 2 film, a Si 3 N 4 film, a BaF 2 film and a CaF 2 film.
Claim 16
Dependent Claim
18 words
A method according to claim 13, wherein the protective film has a thickness of 500 Å or more.
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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) | 1989-08-25 | 1990-02-24 | 1990-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-25 | 1994-02-24 | 1994-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-25 | 1998-02-24 | 1998-08-26 | $7700.00 | Window Closed / Lapsed |