Data storage device with phase lock spin-torque oscillation stabilization

• US 9,390,734 B2
• Filed: 10/09/2015
• Issued: 07/12/2016
• Est. Priority Date: 07/25/2014
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Gao, Kaizhong
• Primary Examiner(s): Cao, Allen T
• Application Number:
  US14/879,906
• Publication Number:
  US 20160035375A1
• Time in Patent Office: 277 Days
• Field of Search: 36012302-12306, 360/125.3, 360/125.06, 360/125.12
• US Class Current: 1/1
• CPC Class Codes: G11B 2005/0024 Microwave assisted recording
• 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 5/11 Shielding of head against electric or magnetic fields
• 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 5/235 Selection of material for gap filler G11B5/232 takes precedence
• CPC Class Codes: G11B 5/3116 Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks G11B5/3113, G11B5/245 take precedence
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence
• CPC Class Codes: G11B 5/3146 magnetic layers
• CPC Class Codes: G11B 5/35 having vibrating elements
• CPC Class Codes: G11B 5/6082 Design of the air bearing surface

Abstract

A data storage device can be configured at least with a first spin-torque oscillator disposed between and contacting a write pole and a shield on an air bearing surface. A second spin-torque oscillator can be disposed between and contact the write pole and shield with the second spin-torque oscillator separated from the air bearing surface by a first stabilization distance and from the first spin-torque oscillator by a second stabilization distance. The first and second spin-torque oscillators can be configured to magnetostatically couple and phase lock to produce a single microwave frequency in response to a bias field.

Claims

1. An apparatus comprising:

a first spin-torque oscillator (STO) disposed between a write pole and a shield on an air bearing surface (ABS), the first STO having a first sidewall oriented at a non-zero angle with respect to an axis extending perpendicular to the ABS; and

a second STO disposed between the write pole and shield, the second STO having a second sidewall oriented at a non-zero angle with respect to the axis extending perpendicular to the ABS, the second STO separated from the ABS by a first stabilization distance and from the first STO by a second stabilization distance, the first and second STOs configured to magnetostatically couple and phase lock to produce a single microwave frequency in response to a bias field.

2. The apparatus of claim 1, wherein the first and second STOs each contact a trailing edge of the write pole and occupy less than all of a write gap between the write pole and shield.

3. The apparatus of claim 1, wherein the single microwave frequency is 5-50 GHz.

4. The apparatus of claim 1, wherein the bias field is 5-15 kOe that passes through the write pole, shield, and each STO.

5. The apparatus of claim 1, wherein the first and second STOs are separated on the ABS from each other and from the write pole.

6. The apparatus of claim 1, wherein the first and second sidewalls are each angled parallel to a write pole sidewall, the write pole sidewall extending from the ABS.

7. An apparatus comprising:

a first spin-torque oscillator (STO) disposed between a write pole and a shield on an air bearing surface (ABS), the first STO contacting a first section of the shield; and

a second STO disposed between the write pole and shield, the second STO contacting a second section of the shield and separated from the ABS by a first stabilization distance and from the first STO by a second stabilization distance, the first and second sections of the shield being separated on the ABS, each STO separated from the write pole and comprising an interlayer separating an injector layer from a generating layer, the first STO configured differently than the second STO to magnetostatically couple and phase lock the first and second STOs to produce a single microwave frequency in response to a bias field.

8. The apparatus of claim 7, wherein the interlayer of the first STO is offset from the interlayer of the second STO, the offset measured parallel to the ABS.

9. The apparatus of claim 7, wherein the respective generating layers of the STOs have different widths, each width measured parallel to the ABS.

10. The apparatus of claim 7, wherein the write pole and shield each have tapered surfaces extending from the ABS at non-normal angles.

11. The apparatus of claim 7, wherein the first STO oscillates at a different frequency than the second STO.

12. The apparatus of claim 7, wherein a width of the injector layer of the first STO is different than a width of the generating layer of the first STO, each width measured parallel to the ABS.

13. The apparatus of claim 7, wherein the first STO has a first length that is less than a second length of a trailing edge of the write pole, each length measured parallel to the ABS.

14. The apparatus of claim 7, wherein the generating layer of the first STO has a width equal to an aggregate width of the interlayer and injector layer, each width measured parallel to the ABS.

15. The apparatus of claim 7, wherein the generating layer of the first STO comprises a different material than the generating layer of the second STO.

16. A method comprising:

positioning a first spin-torque oscillator (STO) between a write pole and a shield on an air bearing surface (ABS), the first STO having a first sidewall oriented parallel to a pole sidewall of the write pole on the ABS;

disposing a second STO between the write pole and shield, the second STO having a second sidewall oriented parallel to the pole sidewall, the second STO separated from the ABS by a first stabilization distance and from the first STO by a second stabilization distance; and

passing a bias field through each STO to magnetostatically couple and phase lock the first and second STOs to generate a single microwave frequency.

17. The method of claim 16, wherein the single microwave frequency alters a data bit on an adjacent data storage medium.

18. The method of claim 16, wherein the phase lock of the STOs produces a single stable oscillation and the single microwave frequency.

19. The method of claim 16, wherein the single microwave frequency is produced concurrently with programming of one or more data bits with the write pole.

20. The method of claim 16, wherein the bias field passes through the STOs in parallel.