Patent EP0398751A2 successfully refreshed from Google Patents.
EP0301823A2
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Three-pole magnetic recording head
Assignee: Digital Equipment Corp
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Filing: 1988-07-27
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Granted: —
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Expires: 2008-07-27
Abstract
Abstract The head includes a read pole (16) disposed between a pair of write poles (12,14) spaced apart to form a gap therebetween. The read pole conducts flux to a flux sensor (22) that is located away from the gap. The head can be utilized for both longitudinal and perpendicular recording and the readback function can be carried out by an inductive coil or flux sensing devices such as a Hall sensor or an MR sensor. The recording head achieves high readback resolution, high write field gradients, and the capability for write wide-read narrow. The read pole and write poles are laminated structures.
Inventors
- 👤 Michael Mallary
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 17:42
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/37; G11B5/372; G11B5/1278; G11B5/187; G11B5/245; G11B5/31; G11B5/3109; G11B5/312; G11B5/313; G11B5/3143; G11B5/332; G11B2005/0002
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
38 words
Magnetic recording head comprising a read pole disposed in a gap between a pair of write poles; and a magnetic flux sensor spaced away from the gap, the read pole adapted to conduct flux to the flux sensor.
Claim 2
Dependent Claim
38 words
Magnetic recording head comprising a read pole disposed in a gap between a pair of write poles; and a magnetic flux sensor spaced away from the gap, the read pole adapted to conduct flux to the flux sensor.
Claim 3
Dependent Claim
16 words
The magnetic recording head of claim 1 wherein the flux sensor is an MR (magneto-resistive) sensor.
Claim 4
Dependent Claim
15 words
The magnetic recording head of claim 1 wherein the flux sensor is a Hall sensor.
Claim 5
Dependent Claim
15 words
The magnetic recording head of claim 1 wherein the flux sensor is an inductive coil.
Claim 6
Dependent Claim
18 words
The magnetic recording head of claim 1 further including magnetically saturable side shields adjacent to the three poles.
Claim 7
Dependent Claim
15 words
The magnetic recording head of claim 1 wherein the read and write poles are laminated.
Claim 8
Dependent Claim
17 words
The magnetic recording head of claim 1 further including write coils surrounding one of the write poles.
Claim 9
Dependent Claim
23 words
The magnetic recording head of claim 1 wherein the read pole comprises a laminate having a thin non-magnetic layer disposed between magnetic layers.
Claim 10
Dependent Claim
14 words
The magnetic recording head of claim 3 wherein the Hall sensor is indium antimonide.
Claim 11
Dependent Claim
15 words
The magnetic recording head of claim 2 wherein the MR sensor includes bismuth and NiFe.
Claim 12
Dependent Claim
19 words
The magnetic recording head of claim 5 wherein the saturable side shield has a thickness of approximately 3 microinches.
Claim 13
Dependent Claim
52 words
The magnetic recording head of claim 6 wherein the laminated write poles comprise a first layer of NiFe or NiFeCo, a second layer of Al₂O₃, a third layer of NiFe or NiFeCo, a fourth layer of Al₂O₃, a fifth seed layer of NiFe or NiFeCo, and a sixth layer of thick NiFeCo.
Claim 14
Independent Claim
52 words
A method for making a three-pole magnetic recording head comprising: 1) preparing a thin laminated seed layer structure; 2) depositing a first magnetic pole on the seed layer structure; 3) ion milling the laminated layers away to leave the first pole; and 4) repeating the process to make the other two poles.
Claim 15
Independent Claim
52 words
A method for making a three-pole magnetic recording head comprising: 1) preparing a thin laminated seed layer structure; 2) depositing a first magnetic pole on the seed layer structure; 3) ion milling the laminated layers away to leave the first pole; and 4) repeating the process to make the other two poles.
Claim 16
Dependent Claim
15 words
The method of claim 13 wherein a magnetic pole is deposited by through mask plating.
Claim 17
Dependent Claim
15 words
The method of claim 13 wherein the magnetic pole is deposited by sheet vacuum deposition.
Claim 18
Dependent Claim
32 words
The method of claim 13 further including depositing a thin ceramic layer over the poles followed by depositing a thin ferromagnetic layer over the ceramic layer to form a saturable side shield.
Claim 19
Dependent Claim
23 words
The magnetic recording head of claim 8 wherein the read pole comprises a thinner layer of Al₂O₃ disposed between thicker layers of NiFeCo.
Claim 20
Dependent Claim
15 words
The magnetic recording head of claim 17 wherein Al₂O₃ layers is approximately 50 Angstroms thick.
References Cited (Backward Citations)
No citation records indexed.
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