EP0443478A2
Expired / Lapsed
EP
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Magnetic recording medium and method for preparing the same
Assignee: Kanegafuchi Chemical Industry Co Ltd
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Filing: 1991-02-18
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Granted: —
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Expires: 2011-02-18
Abstract
Abstract A magnetic recording medium is disclosed, wherein a magnetic film comprising a partially oxidized cobalt with its in-plane coercive force not less than 500 Oe is provided on a substrate. Further disclosed are magnetic recording media, wherein there is further provided an under layer comprising Cr, Fe or an Fe-Co alloy under said magnetic film, and wherein a perpendicular magnetic anisotropic film comprising a partially oxidized metal is further provided on said magnetic film. The magnetic recording media are high in recording density and reproduction output, low in noise and high in S/N ratio.
Inventors
- 👤 Shogo Nasu
- 👤 Koji Saiki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 09:12
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
29 words
A magnetic recording medium, wherein a magnetic film comprising a partially oxidized cobalt with its in-plane coercive force not less than 500 Oe isotropically is provided on a substrate.
Claim 2
Dependent Claim
16 words
The medium according to claim 1, wherein saturation magnetization is in a range of 300-700 emu/cm³.
Claim 3
Dependent Claim
17 words
The medium according to claim 1 or 2, wherein a squareness ratio is not less than 0.6.
Claim 4
Dependent Claim
31 words
The medium according to claim 1 or 2, wherein there is further provided an underlayer comprising Cr, Fe or an Fe-Co alloy under the magnetic film comprising a partially oxidized cobalt.
Claim 5
Dependent Claim
21 words
The medium according to claim 4, wherein the thickness of the under layer is in a range of 10-500 Å .
Claim 6
Dependent Claim
26 words
The medium according to claim 4 or 5, wherein the composition of the Fe-Co alloy is Fe 1 - x Co x (0≦ x ≦ 0.8).
Claim 7
Independent Claim
19 words
The medium according to any of claims 4 to 6, wherein a squareness ratio is not less than 0.6.
Claim 8
Dependent Claim
31 words
The medium according to claim 1 or 2, wherein a perpendicular magnetic anisotropic film comprising a partially oxidized metal is further provided on the magnetic film comprising a partially oxidized cobalt.
Claim 9
Dependent Claim
28 words
The medium according to claim 8, wherein an underlayer comprising Cr, Fe or an Fe-Co alloy is further provided under the magnetic film comprising a partially oxidized cobalt.
Claim 10
Dependent Claim
24 words
The medium according to claim 8 or 9, wherein the partially oxidized metal is a partially oxidized cobalt or a partially oxidized Fe-Co alloy.
Claim 11
Independent Claim
42 words
A method for preparing a magnetic recording medium, wherein a magnetic film comprising a partially oxidized cobalt with its in-plane coercive force not less than 500 Oe isotropically is deposited by sputtering substantially perpendicularly under a pressure not more than 5 mTorr.
Claim 12
Dependent Claim
18 words
The method according to claim 11, wherein the sputtering is carried our by a high-frequency magnetron sputtering method.
Claim 13
Dependent Claim
40 words
The method according to claim 11 or 12, wherein an underlayer comprising Cr, Fe or an Fe-Co alloy is formed by sputtering substantially perpendicularly to the substrate, prior to the deposition of the magnetic film comprising a partially oxidized cobalt.
Claim 14
Dependent Claim
39 words
The method according to claim 11 or 12, wherein the magnetic film comprising a partially oxidized cobalt is first deposited by sputtering and then a perpendicular magnetic anisotropic film comprising a partially oxidized metal is formed thereon by sputtering.
Claim 15
Dependent Claim
28 words
The method according to claim 14, wherein an underlayer comprising Cr, Fe or an Fe-Co alloy is further provided under the magnetic film comprising a partially oxidized cobalt.
References Cited (Backward Citations)
No citation records indexed.
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