White head for high anisotropy media

• US 6,785,092 B2
• Filed: 05/21/2002
• Issued: 08/31/2004
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Covington, Mark William, Parker, Gregory John, Van der Heijden, Petrus Antonius, Crawford, Thomas McLendon
• Primary Examiner(s): KLIMOWICZ, WILLIAM JOSEPH
• Application Number:
  US10/153,129
• Publication Number:
  US 20030026040A1
• Time in Patent Office: 833 Days
• Field of Search: 360/119, 360/125, 360/126, 360/317, 360/318, 360/318.1, 360/321, 360/324, 360/324.1, 360/324.12, 360/121, 360/128
• US Class Current: 360/125.45
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 2005/0002 Special dispositions or recording techniques
• CPC Class Codes: G11B 2005/0005 Arrangements, methods or circuits
• CPC Class Codes: G11B 2005/0029 using magnetisation components of the recording layer disposed mainly perpendicularly to the record carrier surface
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/09 Digital recording
• CPC Class Codes: G11B 5/127 Structure or manufacture of heads, e.g. inductive
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/313 Disposition of layers
• CPC Class Codes: G11B 5/3133 including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure G11B5/3106 takes precedence
• CPC Class Codes: G11B 5/3146 magnetic layers
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy

Abstract

A write head for writing information bits to magnetic storage media includes a first write pole for producing a first magnetic field in a first direction and a second write pole for producing a second magnetic field such that the combined field from the two poles lies either substantially along the first direction or in a second direction that is substantially orthogonal to the first direction. The second write pole includes a free layer having magnetization controlled by spin transfer torque, and a first spacer positioned between the free layer and the first write pole. The write head can further include a pinned layer and a second spacer positioned between the pinned layer and the free layer. A disc drive that includes the write head and a method of writing to magnetic storage media that utilizes the write head are also included.

Claims

1. A write head for writing information bits to magnetic storage media, the write head comprising:

a first write pole for producing a first magnetic field in a first direction; and

a second write pole for producing a second magnetic field such that a combined field from the first and second write poles lies either substantially along the first direction or in a second direction that is substantially orthogonal to the first direction, wherein the second write pole includes a free layer having magnetization controlled by spin transfer torque, and a first spacer positioned between the free layer and the first write pole.

2. A write head according to claim 1, further comprising:

a pinned layer; and

a second spacer positioned between the pinned layer and the free layer.

3. A write head according to claim 2, further comprising:

means for controlling the direction of magnetization in the first write pole; and

means for passing a current through the pinned layer, the second spacer, and the free layer to control the direction of magnetization of the free layer.

4. A write head according to claim 2, wherein the pinned layer comprises one of:

a synthetic antiferromagnet having one layer exchange coupled to either an antiferromagnet or hard magnet, a ferromagnetic exchange layer coupled to an antiferromagnet, a layer of hard magnetic material, or a ferromagnetic layer exchange coupled to a hard magnet.

5. A write head according to claim 2, wherein the second spacer comprises one of:

copper, silver or gold.

6. A write head according to claim 1, wherein the first pole comprises:

a yoke including the first write pole and a return pole; and

a first coil for inducing a magnetic field in the yoke.

7. A disc drive comprising:

means for rotating a magnetic storage medium; and

means for positioning a write head adjacent to a surface of the magnetic storage medium;

wherein the write head includes a first write pole for producing a first magnetic field in a first direction, and a second write pole for producing a second magnetic field such that a combined field from the first and second write poles lies either substantially along the first direction or in a second direction that is substantially orthogonal to the first direction; and

wherein the second write pole includes a free layer having magnetization controlled by spin transfer torque, and a first spacer positioned between the free layer and the first write pole.

8. A disc drive according to claim 7, wherein the write head further comprises:

a pinned layer; and

a second spacer positioned between the pinned layer and the free layer.

9. A disc drive according to claim 8, further comprising:

means for controlling the direction of magnetization in the first write pole; and

means for passing a current through the pinned layer, the second spacer, and the free layer to control the direction of magnetization of the free layer.

10. A disc drive according to claim 8, wherein the pinned layer comprises one of:

a synthetic antiferromagnet having one layer exchange coupled to either an antiferromagnet or hard magnet, a ferromagnetic exchange layer coupled to an antiferromagnet, a layer of hard magnetic material, or a ferromagnetic layer coupled exchange coupled to a hard magnet.

11. A disc drive according to claim 8, wherein the second spacer comprises one of:

copper, silver or gold.

12. A disc drive according to claim 7, wherein the first pole comprises:

a yoke including the first write pole and a return pole; and

a first coil for inducing a magnetic field in the yoke.

13. A method of writing to magnetic storage media, the method comprising:

using a first write pole and a second write pole to produce a first magnetic field in a first direction to create a first change in the direction of magnetization of magnetic domains in the magnetic storage media;

removing the first magnetic field; and

using the first write pole and the second write pole to produce a second magnetic field lying substantially orthogonal to the first direction to switch the direction of magnetization of the magnetic domains in the magnetic storage media, wherein one of the first and second write poles includes a free layer having magnetization controlled by spin transfer torque.

14. The method of claim 13, wherein the first magnetic field is oriented in one of a down track direction or a cross track direction.

15. The method of claim 13, wherein each of the first and second magnetic fields has a magnitude less than the magnetic anisotropy of the magnetic storage media.

16. The method of claim 13, wherein the magnetic storage media comprises:

a disc having a top layer of hard magnetic material and a bottom layer of soft magnetic material adjacent to the top layer of hard magnetic material.

17. The method of claim 13, wherein the step of using a first write pole and a second write pole to produce a first magnetic field in a first direction comprises applying a first current pulse to the first write pole and a second current pulse to the second write pole, and wherein the step of using the first write pole and the second write pole to produce a second magnetic field comprises applying a third current pulse to a second write pole.

18. The method of claim 17, wherein transitions between the second and third current pulses are separated in time by a period less than a relaxation time of the magnetic storage media.

19. The method of claim 13, wherein the step of using a first write pole to produce a first magnetic field in a first direction comprises applying a sequence of current pulses to the first write pole, wherein the current pulses are timed to suppress spin precession of the free layer in the first write pole.

20. The method of claim 19, wherein the step of producing a second magnetic field comprises applying additional current pulses to the second write pole.