Method of resetting AP pinned layers with a canted field

• US 20050011066A1
• Filed: 05/28/2004
• Published: 01/20/2005
• Est. Priority Date: 03/21/2002
• Status: Active Grant

• Current Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Gill, Hardayal Singh, Mackay, Kenneth Donald, Li, Jinshan, Nishioka, Kouichi, Tran, Andy Cuong
• Granted Patent: US 7,370,404 B2
• Time in Patent Office: Days
• US Class Current: 29/603.80
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 2005/0008 Magnetic conditionning of heads, e.g. biasing
• CPC Class Codes: G11B 2005/0016 of magnetoresistive transducers
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: 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
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3932 Magnetic biasing films
• CPC Class Codes: Y10T 29/49021 Magnetic recording reproducing transducer [e.g., tape head, core, etc.]
• CPC Class Codes: Y10T 29/49032 Fabricating head structure or component thereof
• CPC Class Codes: Y10T 29/49034 Treating to affect magnetic properties
• CPC Class Codes: Y10T 29/49043 Depositing magnetic layer or coating
• CPC Class Codes: Y10T 29/49044 Plural magnetic deposition layers

Abstract

A spin valve sensor in a read head has a spacer layer which is located between a self-pinned AP pinned layer structure and a free layer structure. The free layer structure is longitudinally stabilized by first and second hard bias layers which abut first and second side surfaces of the spin valve sensor. The AP pinned layer structure has an antiparallel coupling layer (APC) which is located between first and second AP pinned layers (AP1) and (AP2). The invention employs a resetting process for setting of the magnetic moments of the AP pinned layers by applying a field at an acute angle to the head surface in a plane parallel to the major planes of the layers of the sensor. The resetting process sets a proper polarity of each AP pinned layer, which polarity conforms to processing circuitry employed with the spin valve sensor.

Claims

1. A method for resetting pinned layer magnetization in a magnetoresistive sensor having an air bearing surface, the method comprising:

applying a magnetic field to the sensor, and wherein;

the magnetic field is directed at angle of between 35 and 55 degrees with respect to the ABS; and

the magnetic field has a strength of from 40 to 60 KOe.

2. A method as in claim 1 wherein the reset magnetic field has a strength of about 50 KOe.

3. A method as in claim 1 wherein the magnetic field is applied at angle of about 45 degrees with respect to the ABS.

4. A method as in claim 1 further comprising;

forming a plurality of sensors onto a wafer;

slicing the wafer into rows;

lapping a surface of the rows to form the ABS;

and wherein the magnetic field is applied after the lapping procedure.

5. A method as in claim 1 further comprising before applying the magnetic field, testing the sensor to determine whether pinned layer flipping has occurred and only applying the magnetic field if flipping has occurred.

6. A method as in claim 1 further comprising;

forming a plurality of sensors onto a wafer;

slicing the wafer into at least one row;

lapping a surface of the row to form the ABS;

slicing the row into individual sliders; and

wherein the magnetic field is applied after slicing the row into individual sliders.

7. A method as in claim 1 further comprising, before applying the magnetic field, placing the slider into a fixture.

8. A method as in claim 1, wherein the magnetic field is applied in a plane parallel with major plane of sensor.

9. A method as in claim 1 wherein the sensor is a self pinned sensor.

10. A method as in claim 1 wherein the sensor has a pinned layer that is pinned by exchange coupling with a layer of antiferromagnetic material.

11. A method of constructing a sensor, comprising:

forming a magnetic pinned layer structure the layer having a surface defining a plane;

forming a spacer layer;

forming a magnetic free layer structure;

lapping in a plane perpendicular to the plane of the pinned layer surface to define an air bearing surface; and

applying a high strength magnetic field to the pinned layer structure the magnetic field being applied in a plane generally parallel with the plane defined by the surface of the pinned layer structure and canted with respect to the ABS surface.

12. A method as in claim 11, wherein the magnetic field is applied in a plane that is 35 to 50 degrees with respect to the ABS.

13. A method as in claim 11, wherein the magnetic field is applied in a plane that is about 45 degrees with respect to the ABS.

14. A method as in claim 11, wherein the magnetic field has a strength of 40 KOe to 50 KOe.

15. A method as in claim 11, wherein the forming the pinned layer structure comprises:

depositing a first magnetic layer;

depositing a non-magnetic electrically conductive coupling layer; and

depositing a second magnetic layer.

16. A method as in claim 11, wherein the forming the pinned layer comprises:

depositing a layer of antiferromagnetic material;

depositing a first magnetic layer;

depositing a non-magnetic electrically conductive coupling layer; and

depositing a second magnetic layer.

17. A method for constructing a plurality of magnetoresistive sensors, comprising:

forming a plurality of magnetoresistive sensors on a wafer, each sensor including a magnetic pinned layer structure, a magnetic free layer structure and a spacer layer sandwiched between the pinned layer structure and the free layer structure, the pinned layer structure, free layer structure and spacer layer being formed in parallel planes;

slicing the wafer into one or more rows each row containing a plurality of sensors;

performing a lapping procedure the row to define an air bearing surface in a plane perpendicular to the parallel planes of the pinned layer structure, free layer and spacer layer; and

applying a magnetic field to the row of sensors the magnetic field being directed at parallel to the plane of the pinned layer structure, the free layer and the spacer layer, and being directed at an angle of 35 to 55 degrees with respect to the plane of the ABS surface.

18. A method as in claim 17, wherein the magnetic field is applied at an angle of about 45 degrees with respect to the ABS.

19. A method as in claim 17, wherein the magnetic field has a strength of 40 to 60 KOe.

20. A method as in claim 17, wherein the magnetic field has a strength of about 50 KOe.

21. A method as in claim 17, wherein the forming the pinned layer structure includes:

forming a first magnetic layer;

forming an non-magnetic, electrically conductive spacer layer over the first magnetic layer; and

forming a second magnetic layer over the non-magnetic, electrically conductive spacer layer.