Magnetoresistive element with nano-crystalline shield

• US 8,917,484 B2
• Filed: 03/12/2013
• Issued: 12/23/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Gong, Jie, Tabakovic, Ibro, Riemer, Steve, Kautzky, Michael Christopher
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US13/797,208
• Publication Number:
  US 20140269235A1
• Time in Patent Office: 651 Days
• Field of Search: 360/319, 360/317, 360/324.1, 360/324.11, 360/324.12, 360/324.2, 360/125.31
• US Class Current: 360/319
• CPC Class Codes: G01R 33/0076 Protection, e.g. with housings against stray fields
• CPC Class Codes: G01R 33/025 Compensating stray fields G01R33/0017 takes precedence
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 5/112 Manufacture of shielding device
• 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

Abstract

A magnetoresistive data writer and reader may be generally configured at least with a magnetoresistive (MR) element contacting a magnetic shield that is constructed of (Ni₇₈Fe₂₂)_99.8O_0.2 material. The magnetic shield may be formed with an electrodeposition process that uses β-diketones derivatives to form nano-crystalline grain structure after a subsequent annealing at temperatures above 400° C.

Claims

1. An apparatus comprising a magnetoresistive (MR) element contacting a magnetic shield comprising (Ni₇₈Fe₂₂)_99.8O_0.2 with a grain size of 12nm or less.

2. The apparatus of claim 1, wherein the MR element comprises a trilayer magnetic stack having dual magnetically free layers without a fixed magnetization.

3. The apparatus of claim 1, wherein the MR element comprises an abutted junction magnetic stack having fixed and free magnetization layers.

4. The apparatus of claim 1, wherein the magnetic shield has a grain size of approximately 8-12nm.

5. The apparatus of claim 1, wherein the MR element comprises a data writer having write and return poles.

6. The apparatus of claim 5, wherein the data writer comprises a laser for heat assisted magnetic recording (HAMR).

7. A method comprising:

electrodepositing a magnetic shield of (Ni₇₈Fe₂₂)_99.8O_0.2; and

contacting a magnetoresistive (MR) element with the magnetic shield on an air bearing surface (ABS).

8. The method of claim 7, wherein the magnetic shield is electrodeposited in a bath of a plurality of chemicals.

9. The method of claim 8, wherein the bath comprises at least one β

-diketones derivative.

10. The method of claim 9, wherein a β

-diketones derivative comprises 1,3-Indandione.

11. The method of claim 9, wherein a β

-diketones derivative comprises 2-Aryliden.

12. The method of claim 9, wherein a β

-diketones derivative comprises acetylacetone.

13. The method of claim 9, wherein a β

-diketones derivative comprises 3-methyl acetylacetone.

14. The method of claim 9, wherein multiple β

-diketones derivatives are used during electrodeposition.

15. The method of claim 8, wherein the bath comprises multiple different salts, C₁₂H₂₅SO₄Na, NH₄C1, and H₃BO₃.

16. A method comprising:

forming a magnetic shield of (Ni₇₈Fe₂₂)_99.8O_0.2;

annealing the magnetic shield to a temperature above 400°

C.; and

contacting a magnetoresistive (MR) element with the magnetic shield on an air bearing surface (ABS).

17. The method of claim 16, wherein the annealing step is conducted at approximately 450°

C.

18. The method of claim 17, wherein the annealing step is conducted for approximately for approximately 2 hours or less along a magnetically easy axis of the magnetic shield.

19. The method of claim 17, wherein the annealing step further comprises annealing at approximately 325°

C. for approximately 4 hours along a magnetically hard axis for the magnetic shield.

20. The method of claim 16, wherein the magnetic shield has multiple magnetizations oriented in a stable loop.