Patent US4621030A successfully refreshed from Google Patents.
US4621030A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Perpendicular magnetic recording medium and manufacturing method thereof
Assignee: HGST Japan Ltd
•
Filing: 1983-07-13
•
Granted: 1986-11-04
•
Expires: 2003-07-13
Abstract
Abstract A perpendicular magnetic recording medium free from spike noise having a high permeability magnetic material film, an antiferromagnetic material film and a perpendicularly oriented magnetic material film formed on a substrate in this order. Another high permeability magnetic material film may be formed between the antiferromagnetic material film and the perpendicularly oriented magnetic material film. During the formation of the antiferromagnetic material film, a magnetic field is applied in a direction of a track width.
Inventors
- 👤 Yasutaro Uesaka
- 👤 Hideo Fujiwara
- 👤 Sadao Hishiyama
- 👤 Kazuo Shiiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:59
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/676; G11B2005/0002; G11B2005/0026; G11B2005/0029; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438; Y10T428/12465; Y10T428/12493; Y10T428/12535; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/12937; Y10T428/12944; Y10T428/12951
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
43 words
A perpendicular magnetic recording medium comprising a substrate, a high permeability magnetic material film formed on said substrate, an antiferromagnetic material film formed on said high permeability magnetic material film, and a perpendicularly oriented magnetic material film formed over said antiferromagnetic material film.
Claim 2
Dependent Claim
43 words
A perpendicular magnetic recording medium comprising a substrate, a high permeability magnetic material film formed on said substrate, an antiferromagnetic material film formed on said high permeability magnetic material film, and a perpendicularly oriented magnetic material film formed over said antiferromagnetic material film.
Claim 3
Dependent Claim
27 words
A perpendicular magnetic recording medium according to claim 1 having an amorphous material film formed between said antiferromagnetic material film and said perpendicularly oriented magnetic material film.
Claim 4
Dependent Claim
20 words
A perpendicular magnetic recording medium according to claim 1 wherein a thickness of said antiferromagnetic material film is 20-2000 Å.
Claim 5
Dependent Claim
31 words
A perpendicular magnetic recording medium according to claim 1 wherein the easy axis of magnetization of said high permeability magnetic material film is in the direction of track width in recording.
Claim 6
Dependent Claim
29 words
A perpendicular magnetic recording medium according to claim 1 wherein the material of said antiferromagnetic material film is a Fe-Mn alloy having a Fe content of 45-55 atomic percent.
Claim 7
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 1 wherein the thickness of said perpendicularly oriented magnetic material film is 0.03-0.5 μm.
Claim 8
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 6 wherein the thickness of said perpendicularly oriented magnetic material film is 0.1-0.2 μm.
Claim 9
Dependent Claim
81 words
A perpendicular magnetic recording medium according to claim 1, said perpendicular magnetic recording medium having been subjected to a heat treatment so as to provide a medium having a better perpendicular orientation of magnetization than that of the same medium prior to said heat treatment, wherein the Curie temperature of said high permeability magnetic material film is higher than the temperature of said heat treatment and the Neel temperature of said antiferromagnetic material film is higher than said heat treatment temperature.
Claim 10
Dependent Claim
38 words
A perpendicular magnetic recording medium according to claim 1 wherein said antiferromagnetic material film is a film that has been formed in the presence of a magnetic field, the magnetic field having been applied in a predetermined direction.
Claim 11
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 9 wherein said predetermined direction is the direction of track width in recording.
Claim 12
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 9 wherein said magnetic field has an intensity of at least 2 Oersteds.
Claim 13
Dependent Claim
29 words
A perpendicular magnetic recording medium according to claim 9 wherein said high permeability magnetic material film is a film formed while applying a magnetic field in said predetermined direction.
Claim 14
Dependent Claim
60 words
A perpendicular magnetic recording medium according to claim 9 wherein said medium has been subjected to a heat treatment so as to provide a medium having a batter perpendicular orientation of magnetization than that of the same medium prior to said heat treatment, the medium having been subjected to a magnetic field in said predetermined direction during said heat treatment.
Claim 15
Dependent Claim
40 words
A perpendicular magnetic recording medium according to claim 1 wherein the antiferromagnetic material film is made of a material selected from the group consisting of CoF 3 , FeF 3 , NiO, FeS, VS, α-Fe 2 O 3 and Cr-Mn.
Claim 16
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 1 wherein the high permeability magnetic material film has a thickness of 0.1-5.0 μm.
Claim 17
Dependent Claim
34 words
A perpendicular magnetic recording medium according to claim 2 wherein said amorphous material film is made of a material selected from the group consisting of SiO 2 , Al 2 O 3 and metals.
Claim 18
Dependent Claim
20 words
A perpendicular magnetic recording medium according to claim 2 wherein the amorphous material film has a thickness of 20-500 Å.
Claim 19
Dependent Claim
26 words
A perpendicular magnetic recording medium according to claim 8 wherein, during said heat treatment, said medium is subjected to a magnetic field in a predetermined direction.
Claim 20
Dependent Claim
61 words
A perpendicular magnetic recording medium comprising a substrate, a first high permeability magnetic material film formed on said substrate, an antiferromagnetic material film formed on said first high permeability magnetic material film, a second high permeability magnetic material film formed on said antiferromagnetic material film, and a perpendicularly oriented magnetic material film formed on said second high permeability magnetic material film.
Claim 21
Dependent Claim
61 words
A perpendicular magnetic recording medium comprising a substrate, a first high permeability magnetic material film formed on said substrate, an antiferromagnetic material film formed on said first high permeability magnetic material film, a second high permeability magnetic material film formed on said antiferromagnetic material film, and a perpendicularly oriented magnetic material film formed on said second high permeability magnetic material film.
Claim 22
Dependent Claim
28 words
A perpendicular magnetic recording medium according to claim 19 wherein said second high permeability magnetic material film on said antiferromagnetic material film is made of an amorphous metal.
Claim 23
Dependent Claim
20 words
A perpendicular magnetic recording medium according to claim 19 wherein the thickness of said antiferromagnetic material film is 20-2000 Å.
Claim 24
Dependent Claim
54 words
A perpendicular magnetic recording medium according to claim 19 wherein the easy axis of magnetization of said first high permeability magnetic material film on said substrate or of said second high permeability magnetic material film on said substrate and on said antiferromagnetic material film is in a direction of the track width in recording.
Claim 25
Dependent Claim
29 words
A perpendicular magnetic recording medium according to claim 19 wherein the material of said antiferromagnetic material film is a Fe-Mn alloy having a Fe content of 45-55 atomic percent.
Claim 26
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 19 wherein the thickness of said perpendicularly oriented magnetic material film is 0.03-0.5 μm.
Claim 27
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 24 wherein the thickness of said perpendicularly oriented magnetic material film is 0.1-0.2 μm.
Claim 28
Dependent Claim
84 words
A perpendicular magnetic recording medium according to claim 19, said perpendicular magnetic recording medium having been subjected to a heat treatment so as to provide a medium having a better perpendicular orientation of magnetization than that of the same medium prior to said heat treatment, wherein the Curie temperature of the first and second high permeability magnetic material films are higher than the temperature of said heat treatment and the Neel temperature of said antiferromagnetic material layer is higher than said heat treatment temperature.
Claim 29
Dependent Claim
26 words
A perpendicular magnetic recording medium according to claim 26 wherein, during said heat treatment, said medium is subjected to a magnetic field in a predetermined direction.
Claim 30
Dependent Claim
38 words
A perpendicular magnetic recording medium according to claim 19 wherein said antiferromagnetic material film is a film that has been formed in the presence of a magnetic field, the magnetic field having been applied in a predetermined direction.
Claim 31
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 28 wherein said predetermined direction is the direction of track width in recording.
Claim 32
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 28 wherein said magnetic field has an intensity of at least 2 Oersteds.
Claim 33
Dependent Claim
30 words
A perpendicular magnetic recording medium according to claim 28 wherein said first high permeability magnetic material film is a film formed while applying a magnetic field in said predetermined direction.
Claim 34
Dependent Claim
30 words
A perpendicular magnetic recording medium according to claim 31 wherein said second high permeability magnetic material film is a film formed while applying a magnetic field in said predetermined direction.
Claim 35
Dependent Claim
60 words
A perpendicular magnetic recording medium according to claim 28 wherein said medium has been subjected to a heat treament so as to provide a medium having a better perpendicular orientation of magnetization than that of the same medium prior to said heat treatment, the medium having been subjected to a magnetic field in said predetermined direction during said heat treatment.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-11-03 | 1990-05-05 | 1990-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-03 | 1994-05-05 | 1994-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-03 | 1998-05-05 | 1998-11-04 | $7700.00 | Window Closed / Lapsed |