EP0093838A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Perpendicular magnetic recording medium and method for producing the same
Assignee: Teijin Ltd
•
Filing: 1983-02-16
•
Granted: —
•
Expires: 2003-02-16
Abstract
Abstract A magnetic recording medium conventionally utilizes the in-plane magnetization mode, but recently the perpendicular magnetization mode utilizing the perpendicular anisotropy of an hcp cobalt alloy layer, in which the C axis is oriented perpendicular to the layer surface, has been proposed. The known perpendicular magnetic recording medium is produced by means of RF sputtering and comprises a Permalloy layer, as layer of a low coercive-force material, between the nonmagnetic base and the hcp cobalt alloy layer. The perpendicular anisotropy attained by the present invention in very excellent and is superior to that of a perpendicular recording medium having no Permalloy layer because a Co-Ta alloy is used as the layer of a low coercive-force material.
Inventors
- 👤 Sadao Kadokura
- 👤 Kazuhiko Honjo
- 👤 Takashi Tomie
- 👤 Masahiko Naoe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 03:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/851; G11B5/62; G11B5/64; G11B5/66; G11B5/672
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
75 words
A perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, i.e. a layer of low-coercive force material; and a cobalt alloy layer and which has a direction of easy magnetization in a direction perpendicular to the film surface, characterized in that said layer of low-coercive force material consists of an alloy (hereinafter referred to as Co-Ta alloy) which is mainly composed of cobalt and additionally tantalum.
Claim 2
Dependent Claim
75 words
A perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, i.e. a layer of low-coercive force material; and a cobalt alloy layer and which has a direction of easy magnetization in a direction perpendicular to the film surface, characterized in that said layer of low-coercive force material consists of an alloy (hereinafter referred to as Co-Ta alloy) which is mainly composed of cobalt and additionally tantalum.
Claim 3
Dependent Claim
23 words
A perpendicular magnetic recording medium according to claim 1, wherein a Ta concentration of said Co-Ta alloy is at least 6.4 atomic %.
Claim 4
Dependent Claim
15 words
A perpendicular magnetic recording medium according to claim 2, wherein said Co-Ta alloy is amorphous.
Claim 5
Dependent Claim
17 words
A perpendicular magnetic recording medium according to claim 1, wherein said cobalt alloy layer additionally contains Cr.
Claim 6
Dependent Claim
19 words
A perpendicular magnetic recording medium according to claim 1, wherein said cobalt alloy layer additionally contains Cr and Ta.
Claim 7
Dependent Claim
61 words
A perpendicular magnetic recording medium according to claim 5, wherein the Cr concentration of said cobalt alloy layer is from 2 atomic % to 10 atomic %,with the provision that sum of Ta and Cr concentration is 27 atomic % at the highest and the Ta concentration of said cobalt alloy layer is from 2 atomic % to 10 atomic %.
Claim 8
Dependent Claim
16 words
A perpendicular nonmagnetic according to claim 1, wherein said nonmagnetic base is a polyethylene terephtalate film.
Claim 9
Independent Claim
179 words
A method for producing a perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, i.e. a layer of low-coercive force material; and a cobalt alloy layer and which has a direction of easy magnetization in a direction perpendicular to the film surface, characterized in that said layer of low-coercive force material consists of an alloy (hereinafter referred to as Co-Ta alloy) which is mainly composed of cobalt and additionally tantalum, said method comprising the steps of: forming a layer of said Co-Ta alloy by sputtering method, (hereinafter referred to as an opposing target sputtering method) a magnetic field is generated in a direction perpendicular to the surfaces of a pair of targets (T 1 , T2) arranged opposite to one another within a sputtering device, and depositing material of said targets on the nonmagnetic base (40), which is located beside a space between said pair of targets (T 1 , T 2 ) and which faces said space; and, forming said cobalt alloy layer by the opposing target sputtering method.
Claim 10
Independent Claim
179 words
A method for producing a perpendicular magnetic recording medium comprising a nonmagnetic base, and two magnetic layers successively formed on said nonmagnetic base, i.e. a layer of low-coercive force material; and a cobalt alloy layer and which has a direction of easy magnetization in a direction perpendicular to the film surface, characterized in that said layer of low-coercive force material consists of an alloy (hereinafter referred to as Co-Ta alloy) which is mainly composed of cobalt and additionally tantalum, said method comprising the steps of: forming a layer of said Co-Ta alloy by sputtering method, (hereinafter referred to as an opposing target sputtering method) a magnetic field is generated in a direction perpendicular to the surfaces of a pair of targets (T 1 , T2) arranged opposite to one another within a sputtering device, and depositing material of said targets on the nonmagnetic base (40), which is located beside a space between said pair of targets (T 1 , T 2 ) and which faces said space; and, forming said cobalt alloy layer by the opposing target sputtering method.
Claim 11
Dependent Claim
25 words
A method according to claim 8, wherein said cobalt alloy layer is formed no later than 10 hours after forming said layer of Co-Ta alloy.
Claim 12
Dependent Claim
22 words
A method according to claim 9, wherein said cobalt alloy layer and then said layer of Co-Ta alloy are consecutively formed. -
Claim 13
Dependent Claim
139 words
A sputtering device, comprising: a vacuum vessel; at least one pair of oppositely arranged targets disposed in the vacuum vessel (410); a means (442-445) for generating a magnetic field between said at least one pair of targets (T 1 , T2) in a direction perpendicularly to each of the targets (T 1 , T2), each of said means located behind each of the targets (T 1 , T2); and, at least one pair of conveyable holders (470) for a nonmagnetic base, each of said conveyable holders (470) being located beside a space between said at least one pair of the targets (T 1 , T2), facing said space, and being conveyed in a direction perpendicular to the targets (T 1 , T 2 ), layers having the composition of said targets being deposited on said nonmagnetic base by sputtering.
Claim 14
Dependent Claim
139 words
A sputtering device, comprising: a vacuum vessel; at least one pair of oppositely arranged targets disposed in the vacuum vessel (410); a means (442-445) for generating a magnetic field between said at least one pair of targets (T 1 , T2) in a direction perpendicularly to each of the targets (T 1 , T2), each of said means located behind each of the targets (T 1 , T2); and, at least one pair of conveyable holders (470) for a nonmagnetic base, each of said conveyable holders (470) being located beside a space between said at least one pair of the targets (T 1 , T2), facing said space, and being conveyed in a direction perpendicular to the targets (T 1 , T 2 ), layers having the composition of said targets being deposited on said nonmagnetic base by sputtering.
Claim 15
Dependent Claim
32 words
A sputtering device according to claim 11, wherein one end of said magnetic field generating means, said end being close to said targets, consists of soft magnetic material having a high permeability.
Claim 16
Dependent Claim
23 words
A sputtering device according to claim 12, wherein said end comprises a tip (446) having a pointed configuration at its outside front end.
Claim 17
Dependent Claim
80 words
A sputtering device according to claim 11, wherein said a magnetic field-generating means comprises: a first means (301a, 302a) for generating magnetic field around each of a pair of targets (T 1 , T2), said first means having such a configuration as to surround each of a pair of targets; and, a second means (301, 302) for producing magnetic flux said second means being connected to said first means via a magnetic path formed between the first and second means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.