Stack with wide seed layer

• US 8,822,046 B2
• Filed: 04/30/2012
• Issued: 09/02/2014
• Est. Priority Date: 04/30/2012
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Singleton, Eric Walter, Yi, Jae-Young, Nikolaev, Konstantin, Sapozhnikov, Victor Boris, Wakeham, Stacey Christine, McKinlay, Shaun Eric
• Primary Examiner(s): BERNATZ, KEVIN M
• Application Number:
  US13/460,058
• Publication Number:
  US 20130288076A1
• Time in Patent Office: 855 Days
• Field of Search: None
• US Class Current: 428/811.5
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3912 Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields G11B5/3916 takes precedence
• CPC Class Codes: G11B 5/3932 Magnetic biasing films
• CPC Class Codes: G11B 5/398 Specially shaped layers
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10T 428/1114 having tunnel junction effect
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/1143 with defined structural feature

Abstract

A stack having a seed layer structure with a first part having a first cross-track width and a free layer deposited over the seed layer structure and with a second cross-track width, wherein the first cross-track width is greater than the second cross-track width. In one implementation, the seed layer structure further comprises an antiferromagnetic (AFM) layer and a synthetic antiferromagnetic (SAF) layer. In one alternate implementation, the cross-track width of the seed layer structure is substantially equal to the combined cross-track width of the free layer and cross-track width of two permanent magnets.

Claims

1. A magnetoresistive sensor comprising:

a seed layer structure with a first part having a first cross-track width;

a free layer deposited over the seed layer structure and with a second cross-track width; and

wherein the seed layer structure comprises an antiferromagnetic (AFM) layer and the AFM layer and the free layer do not overlap in a cross-track direction and wherein the first cross-track width is greater than the second cross-track width.

2. The magnetoresistive sensor of claim 1 wherein a height of the seed layer structure is greater than the first cross-track width.

3. The magnetoresistive sensor of claim 1 wherein the free layer is located between two permanent magnets and wherein the first cross-track width is substantially equal to combined cross-track width of the two permanent magnets and the second cross-track width.

4. The magnetoresistive sensor of claim 1 further comprising two permanent magnets with the free layer in-between.

5. The magnetoresistive sensor of claim 1 wherein the first part of the seed layer structure is a synthetic antiferromagnetic (SAF) layer.

6. The magnetoresistive sensor of claim 1 wherein the antiferromagnetic (AFM) layer has tapered cross-track width.

7. The magnetoresistive sensor of claim 1 wherein the seed antiferromagnetic (AFM) layer has a trapezoidal shape.

8. A magnetoresistive sensor comprising:

a free layer between a first permanent magnet and a second permanent magnet;

an antiferromagnetic (AFM) layer structure, wherein the AFM layer structure does not overlap the free layer along the cross-track direction, wherein cross-track width of the AFM layer structure is substantially equal to combined cross-track width of the free layer and the permanent magnets.

9. The magnetoresistive sensor of claim 8 wherein the AFM layer structure further comprising:

a tunneling barrier layer located between combination of the free layer and the permanent magnets and the AFM layer structure;

a synthetic antiferromagnetic (SAF) layer adjacent to the tunneling barrier layer; and

a seed layer including AFM material.

10. The magnetoresistive sensor of claim 9 wherein at least part of the SAF layer being adjacent to a shield layer.

11. The magnetoresistive sensor of claim 10 wherein the cross-track width of the part of the SAF layer being adjacent to the shield layer is substantially equal to the cross-track width of the free layer.

12. The magnetoresistive sensor of claim 8 wherein a height of the AFM layer structure is greater than the cross-track width of the AFM layer structure.

13. The magnetoresistive sensor of claim 8 wherein a height of the AFM layer structure is greater than the cross-track width of the free layer.

14. The magnetoresistive sensor of claim 8 wherein cross-track width of at least a part of the AFM layer structure is greater than cross-track width of the free layer.

15. A magnetoresistive sensor comprising:

a free layer;

a synthetic antiferromagnetic (SAF) layer; and

an antiferromagnetic (AFM) layer structure, wherein the AFM layer structure is located on a shield layer with at least a part of the shield layer located between parts of the AFM layer structure along a cross-track direction, wherein cross-track width of at least a part of the AFM layer structure is greater than cross-track width of the free layer.

16. The magnetoresistive sensor of claim 15, wherein the free layer is located between a first permanent magnet and a second permanent magnet along a cross-track direction.