# US 8,542,464 B2 · Write head having recessed magnetic material in gap region

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- Number: US 8,542,464 B2
- Document ID: US8542464B2
- Status: Granted
- Kind: B2
- Application number: 13/367,353
- Filed: 2012-02-06
- Published: 2012-05-31
- Granted: 2013-09-24
- Earliest claimed: 2003-11-12
- Assignees: Headway Technologies, Inc.
- Applicants: Moris Dovek; Glen Garfunkel; Po Kang Wang
- Inventors: Moris Dovek; Glen Garfunkel; Po Kang Wang
- Web page: https://patentgrep.com/patent/US8542464B2

## CPC

- G11B 5/2657: {all the gaps having the same dimension in the direction transverse to the track direction}
- Y10T 29/49021: Magnetic recording reproducing transducer [e.g., tape head, core, etc.]
- Y10T 29/49043: Depositing magnetic layer or coating
- Y10T 29/49044: Plural magnetic deposition layers
- Y10T 29/49046: with etching or machining of magnetic material
- Y10T 29/49048: Machining magnetic material [e.g., grinding, etching, polishing]
- Y10T 29/49052: by etching
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

As track densities increase, it becomes increasingly important, while writing in a given track, not to inadvertently write data in adjoining tracks. This problem has been overcome by limiting the width of material in the ABS plane to what it is at the write gap. The part of the lower pole that is wider than this is recessed back away from the ABS, thereby greatly reducing its magnetic influence on adjacent tracks. Four different embodiments of write heads that incorporate this notion are described together with a description of a general process for their manufacture.

## Claims

### Claim 1

A magnetic write head having an air bearing surface (ABS), comprising:
on a substrate, a flat primary lower magnetic pole having a first length and first and second ends;
at a separation distance over said lower magnetic pole, a flat upper magnetic pole having a second length that is greater than said first length whereby said upper pole has an end, that has a width, that projects beyond said lower pole only at said first end;
said upper pole being magnetically connected to said lower pole at said second end;
between said upper and lower poles, a field coil that is insulated from both said poles;
a secondary lower pole having first and second parts;
while maintaining a constant width, said first part extending upwards from said primary lower pole's first end to a first height;
said second part extending laterally from said first part only towards said ABS in a plane normal to said ABS so as to be in alignment with said upper pole end;
said second part also extending upwards to a second height above said lower pole that is greater than said first height; and
said second part being separated from said upper pole by a layer of non-magnetic material, whereby it forms a write gap across which a longitudinal recording field suitable for recording data forms naturally, said second part having a width, at the write gap, equal to said upper pole width, whereby it defines a track width.

### Claim 2 (depends on 1)

The magnetic write head described in claim 1 wherein the first length of said primary magnetic pole is between about 5 and 25 microns.

### Claim 3 (depends on 1)

The magnetic write head described in claim 1 wherein the separation distance over said lower magnetic pole is between about 0.05 and 0.2 microns.

### Claim 4 (depends on 1)

The magnetic write head described in claim 1 wherein said first height is between about 0.1 and 0.5 microns.

### Claim 5 (depends on 1)

The magnetic write head described in claim 1 wherein said second height is between about 0.1 and 1 microns.