Patent US4820447A successfully refreshed from Google Patents.
Patent US4596646A successfully refreshed from Google Patents.
US4596646A
Expired / Lapsed
US
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Thin-film permanent magnet and method of producing the same
Assignee: Hitachi Ltd
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Filing: 1983-02-23
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Granted: 1986-06-24
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Expires: 2003-02-23
Abstract
Abstract A thin-film permanent magnet which is made of a Co - Pt alloy containing 5-35 atomic-% of Pt. This thin-film permanent magnet can be readily produced by a sputtering method in which the ultimate pressure before the introduction of a sputtering gas is made 5×10 -7 -1×10 -4 Torr. Without any heat treatment, it has a coercivity of 2,000 Oe at the maximum and a remanence of about 8,000-about 18,000 G.
Inventors
- 👤 Masahiro Kitada
- 👤 Hiroshi Yamamoto
- 👤 Masahide Suenaga
- 👤 Noboru Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 17:48
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/14; H01F41/18; C; C22; C22C; C22C19/00; C22C19/07; H01F10/00; H01F10/08; H01F10/10; H01F10/12; H01F10/16; Y; Y10; Y10T; Y10T428/00; Y10T428/11; Y10T428/115
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
109 words
A method of producing a thin-film permanent magnet which comprises forming a thin film of a Co-Pt alloy containing 5-35 atomic-% of Pt and a balance of Co on a substrate by sputtering, using a target including Pt and Co, in a sputtering atmosphere which has been obtained by placing the interior of a sputtering chamber at vacuum under a pressure of 1×10 -5 -5×10 -5 Torr and, thereafter, introducing a sputtering gas into said chamber, whereby a thin-film permanent magnet having a coercivity of at least 500 Oe can be provided without any heat treatment, which magnet is free of whitish blurs and has a substantially saturated coercivity.
Claim 2
Independent Claim
109 words
A method of producing a thin-film permanent magnet which comprises forming a thin film of a Co-Pt alloy containing 5-35 atomic-% of Pt and a balance of Co on a substrate by sputtering, using a target including Pt and Co, in a sputtering atmosphere which has been obtained by placing the interior of a sputtering chamber at vacuum under a pressure of 1×10 -5 -5×10 -5 Torr and, thereafter, introducing a sputtering gas into said chamber, whereby a thin-film permanent magnet having a coercivity of at least 500 Oe can be provided without any heat treatment, which magnet is free of whitish blurs and has a substantially saturated coercivity.
Claim 3
Dependent Claim
22 words
A method of producing a thin-film permanent magnet according to claim 1, wherein the substrate is made of glass, Al or Ti.
Claim 4
Dependent Claim
42 words
A method of producing a thin-film permanent magnet according to claim 1, wherein the sputtering gas comprises argon gas and sputtering is effected under pressure varying from 1×10 -2 to 1×10 -3 Torr employing a target consisting essentially of Co and Pt.
Claim 5
Dependent Claim
35 words
A method of producing a thin-film permanent magnet according to claim 1, wherein said film has a coercivity of at least 400 Oe and a remanence of at least 8,000 G without any heat treatment.
Claim 6
Dependent Claim
23 words
A method of producing a thin-film permanent magnet according to claim 1, wherein the Pt content of said Co-Pt alloy is 10-30 atomic-%.
Claim 7
Dependent Claim
23 words
A method of producing a thin-film permanent magnet according to claim 1, wherein the Pt content of said Co-Pt alloy is 15-25 atomic-%.
Claim 8
Dependent Claim
21 words
A method of producing a thin-film permanent magnet according to claim 1, wherein said film has a thickness of 100-2500 Å.
Claim 9
Dependent Claim
21 words
A method of producing a thin-film permanent magnet according to claim 1, wherein said film has a thickness of 200-1200 Å.
References Cited (Backward Citations)
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Cited
US4164461A
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US4226681A
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US4328080A
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US4430183A
Cited
US4400255A
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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) | 1989-06-23 | 1989-12-23 | 1990-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-23 | 1993-12-23 | 1994-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-23 | 1997-12-23 | 1998-06-24 | $7700.00 | Window Closed / Lapsed |