# US 6,724,584 B2 · Data head and method using a single antiferromagnetic material to pin multiple magnetic layers with differing orientation

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- Number: US 6,724,584 B2
- Document ID: US6724584B2
- Status: Granted
- Kind: B2
- Application number: 10/152,192
- Filed: 2002-05-20
- Published: 2002-09-19
- Granted: 2004-04-20
- Earliest claimed: 1999-02-11
- Assignees: Seagate Technology LLC
- Inventors: Anthony M. Mack; Zheng Gao; Nurul Amin; Sining Mao; Richard Michel
- Web page: https://patentgrep.com/patent/US6724584B2

## CPC

- G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- B82Y 25/00: Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
- B82Y 40/00: Manufacture or treatment of nanostructures
- G11B 5/3903: {using magnetic thin film layers or their effects, the films being part of integrated structures}
- H01F 10/3272: {by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets}
- H01F 41/304: {using temporary decoupling, e.g. involving blocking, Néel or Curie temperature transitions by heat treatment in presence/absence of a magnetic field}
- G11B 5/3113: {for improving the magnetic domain structure or avoiding the formation or displacement of undesirable magnetic domains}
- G11B 5/3163: {Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers}
- H01F 10/3295: {Spin-exchange coupled multilayers wherein the magnetic pinned or free layers are laminated without anti-parallel coupling within the pinned and free layers}
- Y10T 29/49034: Treating to affect magnetic properties
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- 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)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Methods of fabricating spin valve sensors in accordance with the invention include forming a pinning layer from an antiferromagnetic material and forming a synthetic antiferromagnet adjacent the pinning layer. A free ferromagnetic layer is formed, and exchange tabs are formed adjacent outer portions of the free ferromagnetic layer for biasing the free layer. The exchange tabs are formed from the same antiferromagnetic material as the first pinning layer. Then, the magnetic moments of the synthetic antiferromagnet are set, and the magnetic moment of the free ferromagnetic layer is biased, during a single anneal in the presence of a single magnetic field.

## Claims

### Claim 1

A spin valve magnetoresistive sensor comprising:
a first pinning layer formed from an antiferromagnetic material;
a first synthetic antiferromagnet adjacent and in contact with the pinning layer;
a first spacer layer adjacent and in contact with the first synthetic antiferromagnet;
a free ferromagnetic layer adjacent and in contact with the first spacer layer; and
exchange tabs adjacent and in contact with outer portions of the free ferromagnetic layer, wherein the exchange tabs are formed from the same antiferromagnetic material as the first pinning layer.

### Claim 2 (depends on 1)

The spin valve magnetoresistive sensor of claim 1, wherein the first synthetic antiferromagnet further comprises:
a pinned ferromagnetic layer adjacent and in contact with the first pinning layer;
a metal spacer layer adjacent and in contact with the pinned ferromagnetic layer; and
a reference ferromagnetic layer adjacent and in contact with the metal spacer layer such that the reference ferromagnetic layer is positioned between the first spacer layer and the metal spacer layer.

### Claim 3 (depends on 2)

The spin valve magnetoresistive sensor of claim 2, wherein the pinned ferromagnetic layer and the reference ferromagnetic layer of the first synthetic antiferromagnet have substantially the same thickness.

### Claim 4 (depends on 3)

The spin valve magnetoresistive sensor of claim 3, wherein a magnetic moment of the pinned ferromagnetic layer is set in a first direction, wherein a magnetic moment of the reference ferromagnetic layer is set in a second direction antiparallel with the first direction, and wherein a magnetic moment of the free ferromagnetic layer is biased in a third direction perpendicular to the first and second directions.

### Claim 5 (depends on 4)

The spin valve magnetoresistive sensor of claim 4, wherein the first synthetic antiferromagnet is formed on the first pinning layer, the first spacer layer is formed on the first synthetic antiferromagnet, the free ferromagnetic layer is formed on the first spacer layer and the exchange tabs are formed on the free ferromagnetic layer.

### Claim 6 (depends on 5)

The spin valve magnetoresistive sensor of claim 5, and further comprising:
a second spacer layer formed on a central portion of the free ferromagnetic layer between the exchange tabs;
a second synthetic antiferromagnet formed on the second spacer layer; and
a second pinning layer formed on top of the second synthetic antiferromagnet, wherein the second pinning layer is formed from the same antiferromagnetic material as the first pinning layer and the exchange tabs.

### Claim 7 (depends on 4)

The spin valve magnetoresistive sensor of claim 4, wherein the free ferromagnetic layer is formed partially on the exchange tabs, the first spacer layer is formed on the free layer, the first synthetic antiferromagnet is formed on the first spacer layer, and the first pinning layer is formed on the first synthetic antiferromagnet.

### Claim 8 (depends on 1)

A disc drive storage system including the spin valve magnetoresistive sensor of claim 1 positioned adjacent a disc surface.

### Claim 9

A spin valve magnetoresistive sensor comprising:
a pinning layer formed of a first antiferromagnetic material;
a synthetic antiferromagnet adjacent and in contact with the pinning layer, including:
a pinned ferromagnetic layer adjacent and in contact with the pinning layer;
a metal spacer layer adjacent and in contact with the pinned ferromagnetic layer; and
a reference ferromagnetic layer adjacent and in contact with the metal spacer layer, wherein the pinned ferromagnetic layer and the reference ferromagnetic layer of the synthetic antiferromagnet have substantially the same thickness;
a spacer layer adjacent and in contact with the synthetic antiferromagnetic such that the reference ferromagnetic layer is positioned between the spacer layer and metal spacer layer;
a free ferromagnetic layer adjacent and in contact with the spacer layer; and
exchange tabs also formed of the first antiferromagnetic material, and positioned adjacent and in contact with outer portions of the free ferromagnetic layer.

### Claim 10 (depends on 9)

The spin valve magnetoresistive sensor of claim 9, wherein a magnetic moment of the pinned ferromagnetic layer is set in a first direction, wherein a magnetic moment of the reference ferromagnetic layer is set in a second direction antiparallel with the first direction, and wherein a magnetic moment of the free ferromagnetic layer is biased in a third direction perpendicular to the first and second directions.

### Claim 11 (depends on 10)

The spin valve magnetoresistive sensor of claim 10, wherein the synthetic antiferromagnet is formed on the pinning layer, the spacer layer is formed on the synthetic antiferromagnet, the free ferromagnetic layer is formed on the spacer layer and the exchange tabs are formed on the free ferromagnetic layer.

### Claim 12 (depends on 11)

The spin valve magnetoresistive sensor of claim 11 and further comprising:
a second spacer layer formed on a central portion of the free ferromagnetic layer between the exchange tabs;
a second synthetic antiferromagnet formed on the second spacer layer; and
a second pinning layer formed on top of the second synthetic antiferromagnetic, wherein the second pinning layer is also formed from the first antiferromagnetic material.

### Claim 13 (depends on 10)

The spin valve magnetoresistive sensor of claim 10, wherein the free ferromagnetic layer is formed partially on the exchange tabs, the spacer layer is formed on the free ferromagnetic layer, the synthetic antiferromagnet is formed on the spacer layer, and the pinning layer is formed on the synthetic antiferromagnetic.

### Claim 14 (depends on 9)

A disc drive storage system including the spin valve magnetoresistive sensor of claim 9 positioned adjacent a disc surface.

### Claim 15

A spin valve magnetoresistive sensor, comprising:
a synthetic antiferromagnet having first and second antiferromagnetic layers with respective first and second magnetic moments;
a free ferromagnetic layer having a third magnetic moment; and
orienting means for orienting the first and second magnetic moments antiparallel to one another and for biasing the third magnetic moment perpendicular to the first and the second magnetic moments with a single antiferromagnetic material.

### Claim 16 (depends on 15)

The spin valve magnetoresistive sensor of claim 15, wherein the orienting means further comprise an antiferromagnetic pinning layer adjacent and in contact with the synthetic antiferromagnet and antiferromagnetic exchange tabs adjacent and in contact with the free ferromagnetic layer.

### Claim 17 (depends on 16)

The spin valve magnetoresistive sensor of claim 16, wherein the antiferromagnetic pinning layer and the antiferromagnetic exchange tabs are formed of the same antiferromagnetic material.

### Claim 18 (depends on 17)

The spin valve magnetoresistive sensor of claim 17, wherein the first and second ferromagnetic layers of the synthetic antiferromagnet have substantially the same thickness.