Method and system for providing an antiferromagnetically coupled return pole

• US 9,013,836 B1
• Filed: 05/14/2013
• Issued: 04/21/2015
• Est. Priority Date: 04/02/2013
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital (Fremont) LLC (Western Digital Corporation)
• Inventors: Liu, Feng, Mauri, Daniele
• Primary Examiner(s): CASTRO, ANGEL A
• Application Number:
  US13/894,281
• Time in Patent Office: 707 Days
• Field of Search: 360/125.03, 360/125.12, 360/125.16, 360/125.26, 360/319
• US Class Current: 360/319
• CPC Class Codes: G11B 5/115 Shielding devices arranged between heads or windings G11B5/265 , G11B5/29 take precedence
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/147 with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated magnetic layers, e.g. sheets in thin films G11B5/31
• CPC Class Codes: G11B 5/3146 magnetic layers
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence

Abstract

A method and system provide a magnetic head having an air-bearing surface (ABS). The magnetic head includes a read transducer and a write transducer. The read transducer includes a first shield and a read sensor. The write transducer includes a main pole, at least one coil for energizing the main pole and a return pole between the read sensor and the main pole. The return pole includes an antiparallel coupling (AC) pole structure. The AC pole structure includes a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer. The ferromagnetic layers and the nonmagnetic spacer layer(s) are substantially parallel. The ferromagnetic layers and the nonmagnetic spacer layer(s) are substantially perpendicular to the ABS. The magnetic moment of each of the ferromagnetic layers is aligned antiparallel with the magnetic moment of a nearest neighbor of the ferromagnetic layers.

Claims

1. A magnetic head having an air-bearing surface (ABS) and comprising:

a read transducer including a first shield, a second shield and a read sensor between the first shield and the second shield, the second shield including a first ferromagnetic layer having a first magnetic moment, a nonmagnetic spacer layer, and a second ferromagnetic layer having a second magnetic moment, the nonmagnetic spacer layer residing between the first ferromagnetic layer and the second ferromagnetic layer, the first ferromagnetic layer residing between the read sensor and the nonmagnetic spacer layer, the first magnetic moment of the first ferromagnetic layer being coupled antiparallel with the second magnetic moment of the second ferromagnetic layer; and

a write transducer including a main pole, at least one coil for energizing the main pole and a return pole between the second shield of the read transducer and the main pole, the return pole including an antiparallel coupling (AC) pole structure, the AC pole structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, the plurality of ferromagnetic layers and the at least one nonmagnetic layer being substantially parallel, the plurality of ferromagnetic layers and the at least one nonmagnetic spacer layer being substantially perpendicular to the ABS, a magnetic moment of each of the plurality of ferromagnetic layers being aligned antiparallel with the magnetic moment of a nearest neighbor of the plurality of ferromagnetic layers;

wherein the return pole is magnetically decoupled from the second shield if the return pole does not adjoin the second shield; and

wherein at least one of the plurality of ferromagnetic layers is ferromagnetically coupled with the second ferromagnetic layer of the second shield if the return pole adjoins the second shield.

2. The magnetic head of claim 1 further comprising:

a nonmagnetic piggyback layer between the second shield and the return pole.

3. The magnetic head of claim 1 wherein the return pole further includes:

at least one magnetic layer adjacent to the AC pole structure.

4. The magnetic head of claim 1 wherein the return pole further includes:

a first magnetic layer and a second magnetic layer, the AC pole structure residing between the first magnetic layer and the second magnetic layer.

5. The magnetic head of claim 4 wherein the first magnetic layer and the second magnetic layer include NiFe.

6. The magnetic head of claim 1 wherein the write transducer further includes:

a back gap recessed from the ABS and coupling the main pole with the return pole.

7. The magnetic head of claim 1 wherein the return pole has an ABS facing surface and a back surface opposite to the ABS facing surface, the AC pole structure extending from the ABS facing surface to the back surface.

8. The magnetic head of claim 1 wherein the plurality of ferromagnetic layers includes a plurality of CoFe layers.

9. The magnetic head of claim 8 wherein each of the plurality of ferromagnetic layers has a thickness of at least fifty five nanometers and not more than eighty five nanometers.

10. The magnetic head of claim 1 wherein the at least one nonmagnetic layer includes Ru.

11. The head of claim 10 wherein each of the at least one nonmagnetic layer has a thickness of not more than ten Angstroms.

12. The magnetic head of claim 1 each of the plurality of ferromagnetic layers being antiferromagnetically coupled with a nearest neighbor of the plurality of ferromagnetic layers.

13. The magnetic transducer of claim 1 wherein the main pole is magnetically disconnected from the return pole.

14. A magnetic head having an air-bearing surface (ABS) and comprising:

a read transducer including a first shield, a second shield and a read sensor between the first shield and the second shield, the second shield including a first ferromagnetic layer having a first magnetic moment, a nonmagnetic spacer layer and a second ferromagnetic layer having a second magnetic moment, the nonmagnetic spacer layer residing between the first ferromagnetic layer and the second ferromagnetic layer, the first ferromagnetic layer residing between the read sensor and the nonmagnetic spacer layer, the first magnetic moment of the first ferromagnetic layer being coupled antiparallel with the second magnetic moment of the second ferromagnetic layer;

a nonmagnetic piggyback layer; and

a write transducer, the nonmagnetic piggyback layer being between the read transducer and the write transducer, the write transducer including a main pole, at least one coil for energizing the main pole, a back gap and a return pole between the read sensor and the main pole, the return pole including an ABS facing surface and a back surface opposite to the ABS facing surface, the return pole including an antiferromagnetic (AFC) pole structure and at least one NiFe magnetic layer adjoining the AFC pole structure, the AFC pole structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, the plurality of ferromagnetic layers and the at least one nonmagnetic layer being substantially parallel, the plurality of ferromagnetic layers and the at least one nonmagnetic spacer layer being substantially perpendicular to the ABS, a magnetic moment of each of the plurality of ferromagnetic layers being antiferromagnetically coupled with the magnetic moment of a nearest neighbor of the plurality of ferromagnetic layers, the AFC pole structure extending from the ABS facing surface to the back surface, the back gap recessed from the ABS and coupling the main pole with the return pole;

wherein the return pole is magnetically decoupled from the second shield.

15. A disk drive comprising:

a media;

a slider including a having an air-bearing surface (ABS) and including a read transducer and a write transducer, the read transducer including a first shield, a second shield and a read sensor between the first shield and the second shield, the second shield including a first ferromagnetic layer having a first magnetic moment, a nonmagnetic spacer layer, and a second ferromagnetic layer having a second magnetic moment, the nonmagnetic spacer layer residing between the first ferromagnetic layer and the second ferromagnetic layer, the first ferromagnetic layer residing between the read sensor and the nonmagnetic spacer layer, the first magnetic moment of the first ferromagnetic layer being coupled antiparallel with the second magnetic moment of the second ferromagnetic layer, the write transducer including a main pole, at least one coil for energizing the main pole and a return pole between the read sensor and the main pole, the return pole including an antiparallel (AC) pole structure, the AC pole structure including a plurality of ferromagnetic layers interleaved with at least one nonmagnetic layer, the plurality of ferromagnetic layers and the at least one nonmagnetic layer being substantially parallel, the plurality of ferromagnetic layers and the at least one nonmagnetic spacer layer being substantially perpendicular to the ABS, a magnetic moment of each of the plurality of ferromagnetic layers being aligned antiparallel with the magnetic moment of a nearest neighbor of the plurality of ferromagnetic layers;

wherein the return pole is magnetically decoupled from the second shield if the return pole does not adjoin the second shield; and

wherein at least one of the plurality of ferromagnetic layers is ferromagnetically coupled with the second ferromagnetic layer of the second shield if the return pole adjoins the second shield.

16. The disk drive of claim 15 wherein the main pole is magnetically disconnected from the return pole.