US4743491A
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Perpendicular magnetic recording medium and fabrication method therefor
Assignee: Hitachi Ltd
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Filing: 1985-11-01
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Granted: 1988-05-10
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Expires: 2005-11-01
Abstract
Abstract A perpendicular magnetic recording medium according to this invention comprises an electrically conductive underlayer formed on a non-magnetic substrate, in the case where no high permeability magnetic film is deposited, and a magnetic thin film having a perpendicular magnetic anisotrophy is formed thereon. In the case of a so-called double-layer structure including a high permeablilty magnetic film, on the non-magnetic substrate are formed the high permeablilty magnetic film, an intermediate film, and a magnetic thin film one on another in this order. The nearest neighbor's distance of atoms of the underlayer and the intermediate film is not smaller than 0.25 nm (2.5 ANGSTROM ) and not greater than 0.32 nm (3.2 ANGSTROM ) and they are made of at least one selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, Ti, nitrides and oxides of these elements.
Inventors
- 👤 Seiichi Asada
- 👤 Hiroyuki Suzuki
- 👤 Toshio Niihara
- 👤 Kazuetsu Yoshida
- 👤 Masaaki Futamoto
- 👤 Yukio Honda
- 👤 Norikazu Tsumita
- 👤 Kazuo Shiiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:30
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/657; G11B5/73; G11B5/7368; G11B5/7369; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
136 words
A method for fabricating a perpendicular magnetic recording medium in which a magnetic thin film whose main component is iron nitride having perpendicular magnetic anisotropy, a nitrogen content of 20 to 32 atom % and a saturation flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 is formed on an electrically conductive underlayer deposited on a non-magnetic substrate by physical evaporation in an Ar stream, a stream of mixed gas of Ar and nitrogen, a nitrogen stream, or a stream of mixed gas of hydrogen and one of said gases, by using iron or iron nitride as starting material, said electrically conductive layer having a thickness of at least 0.01 μm, an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm.
Claim 2
Independent Claim
136 words
A method for fabricating a perpendicular magnetic recording medium in which a magnetic thin film whose main component is iron nitride having perpendicular magnetic anisotropy, a nitrogen content of 20 to 32 atom % and a saturation flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 is formed on an electrically conductive underlayer deposited on a non-magnetic substrate by physical evaporation in an Ar stream, a stream of mixed gas of Ar and nitrogen, a nitrogen stream, or a stream of mixed gas of hydrogen and one of said gases, by using iron or iron nitride as starting material, said electrically conductive layer having a thickness of at least 0.01 μm, an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm.
Claim 3
Dependent Claim
47 words
A method for fabricating a perpendicular magnetic recording medium according to claim 1, in which a bias voltage comprised between -50 V and -500 V with respect to the earth potential is applied to the substrate over which the magnetic thin film is deposited by physical evaporation.
Claim 4
Independent Claim
141 words
A method for fabricating a perpendicular magnetic recording medium in which a magnetic film whose main component is iron nitride having perpendicular magnetic anisotropy, a nitrogen content of 20 to 32 atom % and a saturation flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 is formed on an intermediate layer which is formed on a high permeability magnetic film disposed on a non-magnetic substrate, said intermediate film having an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm, said magnetic thin film being formed by physical evaporation in a Ar stream, a stream of mixed gas of Ar and nitrogen, a nitrogen stream, or a stream of mixed gas of hydrogen and one of said gases, by using iron or iron nitride as starting material.
Claim 5
Independent Claim
141 words
A method for fabricating a perpendicular magnetic recording medium in which a magnetic film whose main component is iron nitride having perpendicular magnetic anisotropy, a nitrogen content of 20 to 32 atom % and a saturation flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 is formed on an intermediate layer which is formed on a high permeability magnetic film disposed on a non-magnetic substrate, said intermediate film having an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm, said magnetic thin film being formed by physical evaporation in a Ar stream, a stream of mixed gas of Ar and nitrogen, a nitrogen stream, or a stream of mixed gas of hydrogen and one of said gases, by using iron or iron nitride as starting material.
Claim 6
Dependent Claim
47 words
A method for fabricating a perpendicular magnetic recording medium according to claim 3, in which a biased voltage comprised between -50 V and -500 V with respect to the earth potential is applied to the substrate over which the magnetic thin film is deposited by physical evaporation.
Claim 7
Dependent Claim
111 words
A perpendicular magnetic recording medium comprising: a non-magnetic substrate; an electrically conductive underlayer deposited on said non-magnetic substrate, said electrically conductive underlayer having a thickness of at least 0.01 μm, an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm; and a magnetic thin film formed on said electrically conductive underlayer, whose main component is iron nitride having perpendicular magnetic anisotropy, wherein the content of nitrogen in said magnetic thin film is 20 to 32 atom % and said magnetic thin film has a saturation magnetic flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 .
Claim 8
Dependent Claim
111 words
A perpendicular magnetic recording medium comprising: a non-magnetic substrate; an electrically conductive underlayer deposited on said non-magnetic substrate, said electrically conductive underlayer having a thickness of at least 0.01 μm, an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm; and a magnetic thin film formed on said electrically conductive underlayer, whose main component is iron nitride having perpendicular magnetic anisotropy, wherein the content of nitrogen in said magnetic thin film is 20 to 32 atom % and said magnetic thin film has a saturation magnetic flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 .
Claim 9
Dependent Claim
33 words
A perpendicular magnetic recording medium according to claim 5, in which the distance between nearest neighbor atoms of said electrically conductive underlayer is not smaller than 0.265 nm and not greater than nm.
Claim 10
Dependent Claim
52 words
A perpendicular magnetic recording medium according to claim 5, in which said electrically conductive underlayer is made of at least one material selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, and electrically conductive nitrides and oxides thereof.
Claim 11
Dependent Claim
38 words
A perpendicular magnetic recording medium according to claim 5, in which said underlayer is made of at least one material selected from the group consisting of Zn, Mo, W, Nb, Ta, Al, Ti, Sn and oxides of Sn.
Claim 12
Dependent Claim
34 words
A perpendicular magnetic recording medium according to claim 5, in which the content of nitrogen in said magnetic thin film is not smaller than 22 atom % and not greater than 28 atom %.
Claim 13
Dependent Claim
36 words
A perpendicular magnetic recording medium according to claim 5, in which the saturation magnetic flux density of said magnetic thin film is not smaller than 0.65 Wb/m 2 and not greater than 1 Wb/m 2 .
Claim 14
Dependent Claim
54 words
A perpendicular magnetic recording medium according to claim 5, in which the magnetic thin film further comprises at least one material selected from the group consisting of Cr, Ni, Co, Bi, elements of the platinum group, Zr, Ta, Nb, Al, and W at a content not greater than 10 atom % together with iron.
Claim 15
Dependent Claim
30 words
A perpendicular magnetic recording medium according to claim 5, in which the thickness of said magnetic thin film is not smaller than 0.1 μm and not greater than 1.0 μm.
Claim 16
Dependent Claim
20 words
A perpendicular magnetic recording medium according to claim 5, wherein said electrically conductive underlayer comprises at least two film layers.
Claim 17
Dependent Claim
24 words
A perpendicular magnetic recording medium according to claim 5, in which the thickness of said electrically conductive underlayer is not greater than 0.2 μm.
Claim 18
Dependent Claim
34 words
A perpendicular magnetic recording medium according to claim 14, in which the distance between nearest neighbor atoms of said electrically conductive underlayer is not smaller than 0.265 nm and not greater than 0.285 nm.
Claim 19
Dependent Claim
52 words
A perpendicular magnetic recording medium according to claim 14, in which said electrically conductive underlayer is made of at least one material selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, and electrically conductive nitrides and oxides thereof.
Claim 20
Dependent Claim
38 words
A perpendicular magnetic recording medium according to claim 14, in which said underlayer is made of at least one material selected from the group consisting of Zn, Mo, W, Nb, Ta, Al, Ti, Sn and oxides of Sn.
Claim 21
Dependent Claim
34 words
A perpendicular magnetic recording medium according to claim 14, in which the content of nitrogen in said magnetic thin film is not smaller than 22 atom % and not greater than 28 atom %.
Claim 22
Dependent Claim
36 words
A perpendicular magnetic recording medium according to claim 14, in which the saturation magnetic flux density of said magnetic thin film is not smaller than 0.65 Wb/m 2 and not greater than 1 Wb/m 2 .
Claim 23
Dependent Claim
54 words
A perpendicular magnetic recording medium according to claim 14, in which the magnetic thin film further comprises at least one material selected from the group consisting of Cr, Ni, Co, Bi, elements of the platinum group, Zr, Ta, Nb, Al, and W at a content not greater than 10 atom % together with iron.
Claim 24
Dependent Claim
30 words
A perpendicular magnetic recording medium according to claim 14, in which the thickness of said magnetic thin film is not smaller than 0.1 μm and not greater than 1.0 μm.
Claim 25
Dependent Claim
110 words
A perpendicular magnetic recording medium comprising: a non-magnetic substrate; a high permeability magnetic film disposed on said non-magnetic substrate; at least an intermediate film formed on said high permeability magnetic film, said intermediate film having an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm; and a magnetic thin film formed on said intermediate film, whose main component is iron nitride having a perpendicular magnetic anisotropy, wherein said magnetic thin film has a nitrogen content of 20 to 32 atom % and a saturation magnetic flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 .
Claim 26
Dependent Claim
110 words
A perpendicular magnetic recording medium comprising: a non-magnetic substrate; a high permeability magnetic film disposed on said non-magnetic substrate; at least an intermediate film formed on said high permeability magnetic film, said intermediate film having an electrical resistivity not greater than 1×10 -1 Ωcm and in which the distance between nearest neighbor atoms is 0.25 nm to 0.32 nm; and a magnetic thin film formed on said intermediate film, whose main component is iron nitride having a perpendicular magnetic anisotropy, wherein said magnetic thin film has a nitrogen content of 20 to 32 atom % and a saturation magnetic flux density of 0.2 Wb/m 2 to 1.0 Wb/m 2 .
Claim 27
Dependent Claim
49 words
A perpendicular magnetic recording medium according to claim 22, in which said intermediate film is made of at least one material selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, and nitrides and oxides thereof.
Claim 28
Dependent Claim
89 words
A perpendicular magnetic recording medium according to claim 22, in which the thickness of said magnetic thin film is not smaller than 0.1 μm and not greater than 1.0 μm; the content of nitrogen in said magnetic thin film is not smaller than 22 atom % and not greater than 28 atom %; and said magnetic thin film is a perpendicularly magnetized film, whose main component is iron nitride having a saturation magnetic flux density not smaller than 0.65 Wb/m 2 and not greater than 1 Wb/m 2 .
Claim 29
Dependent Claim
54 words
A perpendicular magnetic recording medium according to claim 22, in which the magnetic thin film further comprises at least one material selected from the group consisting of Cr, Ni, Co, Bi, elements of the platinum group, Zr, Ta, Nb, Al, and W at a content not greater than 10 atom % together with iron.
Claim 30
Dependent Claim
21 words
A perpendicular magnetic recording medium according to claim 22, wherein said intermediate film has a thickness of at least 0.01 μm.
Claim 31
Dependent Claim
22 words
A perpendicular magnetic recording medium according to claim 22, wherein said intermediate film has a thickness of 0.01 μm to 0.05 μm.
Claim 32
Dependent Claim
33 words
perpendicular magnetic recording medium according to claim 22, in which the distance between nearest neighbor atoms of said electrically conductive underlayer is not smaller than 0.265 nm and not greater than 0.285 nm.
Claim 33
Dependent Claim
18 words
A perpendicular magnetic recording medium according to claim 22, wherein said intermediate film comprises at least two layers.
Claim 34
Dependent Claim
28 words
A perpendicular magnetic recording medium according to claim 22, wherein total thickness of the intermediate film is not smaller than 0.01 μm and not greater than 0.1 μm.
Claim 35
Dependent Claim
49 words
A perpendicular magnetic recording medium according to claim 30, in which said intermediate film is made of at least one material selected from the group consisting of V, Ru, Zn, Os, Rh, Ir, Mo, W, Re, Pd, Pt, Nb, Ta, Sn, Al, Au, Ag, and nitrides and oxides thereof.
Claim 36
Dependent Claim
89 words
A perpendicular magnetic recording medium according to claim 30, in which the thickness of said magnetic thin film is not smaller than 0.1 μm and not greater than 1.0 μm; the content of nitrogen in said magnetic thin film is not smaller than 22 atom % and not greater than 28 atom %; and said magnetic thin film is a perpendicularly magnetized film, whose main component is iron nitride having a saturation magnetic flux density not smaller than 0.65 Wb/m 2 and not greater than 1 Wb/m 2 .
Claim 37
Dependent Claim
54 words
A perpendicular magnetic recording medium according to claim 30, in which the magnetic thin film further comprises at least one material selected from the group consisting of Cr, Ni, Co, Bi, elements of the platinum group, Zr, Ta, Nb, Al, and W at a content not greater than 10 atom % together with iron.
References Cited (Backward Citations)
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