Patent US3289859A successfully refreshed from Google Patents.
EP0095191A2
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Magnetic recording medium
Assignee: Toshiba Corp
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Filing: 1983-05-25
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Granted: —
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Expires: 2003-05-25
Abstract
Abstract Disclosed is a magnetic recording medium which comprises; a substrate; a first magnetic layer applied on the surface of the substrate and having an easy axis of magnetization in the in-plane direction of the substrate; and a second magnetic layer applied on the surface of the first magnetic layer, formed of ferrite series powder represented by the formula:(wherein A is at least one metallic element selected from the group consisting of Ba, Sr, Pb and Ca; M is at least one substituent component selected from the group consisting of CO, Ti, Ni, Mn, Cu, Zn, In, Ge and Nb; m is 0.08 to 0.2; and n is 5.4 to 6.01, and having an easy axis of magnetization in a direction perpendicular to the plane of the substrate; said first magnetic layer having a surface resistivity of 1 × 10<sup>2</sup> to 1 x 10<sup>8</sup>Ω. In another embodiment, a conductive layer having a surface resistivity of 1 x 10<sup>7</sup> Ω or smaller may be interposed between the substrate and the first magnetic layer.
Inventors
- 👤 Shozo Hideyama
- 👤 Akio Ishizawa
- 👤 Katuya Kumagai
- 👤 Minoru Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 04:08
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/716; G11B5/706; G11B5/70626; G11B5/70642; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/30; Y10T428/31504; Y10T428/31507
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
146 words
A magnetic recording medium which comprises; a substrate; a first magnetic layer applied on the surface of the substrate and having an easy axis of magnetization in the in-plane direction of the substrate; and a second magnetic layer applied on the surface of the first magnetic layer, formed of ferrite series powder represented by the formula: (wherein A is at least one metallic element selected from the group consisting of Ba, Sr, Pb and Ca; M is at least one substituent component selected from the group consisting of CO, Ti, Ni, Mn, Cu, Zn, In, Ge and Nb; m is 0.08 to 0.2; and n is 5.4 to 6.0), and having an easy axis of magnetization in a direction perpendicular to the plane of the substrate; said first magnetic layer having a surface resistivity of 1 x 10 2 to 1 x 10 8 Q .
Claim 2
Dependent Claim
146 words
A magnetic recording medium which comprises; a substrate; a first magnetic layer applied on the surface of the substrate and having an easy axis of magnetization in the in-plane direction of the substrate; and a second magnetic layer applied on the surface of the first magnetic layer, formed of ferrite series powder represented by the formula: (wherein A is at least one metallic element selected from the group consisting of Ba, Sr, Pb and Ca; M is at least one substituent component selected from the group consisting of CO, Ti, Ni, Mn, Cu, Zn, In, Ge and Nb; m is 0.08 to 0.2; and n is 5.4 to 6.0), and having an easy axis of magnetization in a direction perpendicular to the plane of the substrate; said first magnetic layer having a surface resistivity of 1 x 10 2 to 1 x 10 8 Q .
Claim 3
Dependent Claim
26 words
The magnetic recording medium according to Claim 1, wherein said first magnetic layer contains 2 to 50 wt.% of carbon black based on a resinous binder.
Claim 4
Dependent Claim
34 words
The magnetic recording medium according to Claim 1, wherein the magnetic powder making up the first magnetic layer is selected from the group consisting of y-ferrite powder, cobalt-substituted y-ferrite powder and chromium oxide powder.
Claim 5
Dependent Claim
21 words
The magnetic recording medium according to Claim 3, wherein the magnetic powder making up the first magnetic layer is y-ferrite powder.
Claim 6
Dependent Claim
21 words
The magnetic recording medium according to Claim 1, wherein the element represented by A of the second magnetic layer is Ba.
Claim 7
Dependent Claim
30 words
The magnetic recording medium according to Claim 5, wherein the second magnetic layer is formed of BaO 5.8(Fe 1 - 0.1 CO 0.1 Ti 0.1 ) 2 O 3 powder.
Claim 8
Dependent Claim
34 words
The magnetic recording medium according to Claim 1, wherein a conductive layer having a surface resistivity of 1 x 10 7 Ω or smaller is interposed between the substrate and the first magnetic layer.
Claim 9
Dependent Claim
26 words
The magnetic recording medium according to Claim 7, wherein said first magnetic layer contains 2 to 50 wt.% of carbon black based on a resinous binder.
Claim 10
Dependent Claim
33 words
The magnetic recording medium according to Claim 7, wherein magnetic powder making up the first magnetic layer is selected from the group consisting of y-ferrite powder, cobalt-substituted y-ferrite powder and chromium oxide powder.
Claim 11
Dependent Claim
20 words
The magnetic recording medium according to Claim 9, wherein magnetic powder making up the first magnetic layer is y-ferrite powder.
Claim 12
Dependent Claim
22 words
ll. The magnetic recording medium according to Claim 6, wherein the element represented by A of the second magnetic layer is Ba.
Claim 13
Dependent Claim
26 words
The magnetic recording medium according to Claim ll, wherein the second magnetic layer is formed of BaO·5.8(Fe 1-0.1 CO 0.1 Ti 0.1 ) 2 O 3
Claim 14
Dependent Claim
49 words
The magnetic recording medium according to Claim 7, wehrein neither the first magnetic layer nor the second magnetic layer contains any conductive material and the conductive layer having a surface resistivity of 1 x 10 7 Ω or smaller is interposed between the substrate and the first magnetic layer.
References Cited (Backward Citations)
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