Microwave assisted magnetic recording (MAMR) write head and system

• US 9,142,227 B1
• Filed: 09/08/2014
• Issued: 09/22/2015
• Est. Priority Date: 09/08/2014
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Etoh, Kimitoshi, Hatatani, Masahiko, Hosomi, Kazuhiko, Maruyama, Yohji, Sugiura, Kenji, Sugiyama, Mikito
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US14/480,394
• Time in Patent Office: 379 Days
• Field of Search: 360/125.3, 360/125.31, 360/125.06, 360/125.16, 360/125.27, 360/125.28, 360/125.29, 360/125.03
• US Class Current: 1/1
• CPC Class Codes: G11B 2005/0024 Microwave assisted recording
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• 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 5/3133 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

Abstract

A microwave-assisted magnetic recording (MAMR) write head includes a yoke structure with a main pole, a flux return pole, and a trailing magnetic shield. The main pole includes a write pole with a tip at the disk-facing surface, a sub pole with an end recessed from the disk-facing surface and an electrically insulating layer between the write pole and the sub pole. The spin-torque oscillator (STO) is located at the disk-facing surface between the trailing shield and the write pole tip. The insulating layer assures that the STO current is not shorted between the return pole and the write pole. The insulating layer between the write pole and the sub pole increases the area of the junction between the return pole and write pole, which reduces the magnetic reluctance of the yoke structure.

Claims

1. A microwave-assisted magnetic recording (MAMR) write head for magnetizing regions in a magnetic recording layer, the write head comprising:

a head carrier having a generally planar first surface and a surface for facing the recording layer that is generally orthogonal to said first surface;

a main pole on the first surface comprising a write pole having a tip substantially at the recording-layer-facing surface, a sub pole and an electrically insulating layer between the write pole and the sub pole;

a return pole having an end substantially at the recording-layer-facing surface;

a yoke stud of magnetically permeable material connecting and magnetically coupling the return pole to the sub pole, the yoke stud being in direct contact with the sub pole, wherein there is no insulating material between the yoke stud and the sub pole;

an electrically conductive pancake coil between the main pole and the return pole, the pancake coil having sections wherein all of said sections lie in substantially the same plane and are wrapped around the yoke stud;

a trailing shield substantially at the recording-layer-facing surface and magnetically coupled to the return pole; and

a spin torque oscillator (STO) substantially at the recording-layer-facing surface between the trailing shield and the write pole tip;

wherein the return pole, trailing shield and write pole provide an electrically conductive path for electrical current to the STO.

2. The head of claim 1 wherein the sub pole has an end facing the recording-layer-facing surface but recessed from the recording-layer-facing surface.

3. The head of claim 1 wherein the sub pole has a thickness greater than the thickness of the write pole.

4. The head of claim 1 wherein the electrically insulating layer has a thickness greater than or equal to 2 nm.

5. The head of claim 1 wherein the electrically insulating layer is formed of a material selected from Al₂O₃, SiC, SiN, diamond-like carbon (DLC), SiO₂ and MgO.

6. The head of claim 1 further comprising an electrically conductive lead connected to the write pole at a region recessed from the recording-layer-facing surface.

7. The head of claim 1 further comprising a leading shield substantially at the recording-layer-facing surface, the write pole tip being located between the leading shield and the trailing shield.

8. A MAMR system comprising:

the write head of claim 1; and

a magnetic recording medium having a perpendicular magnetic recording layer.

9. A microwave-assisted magnetic recording (MAMR) write head for magnetizing regions in a perpendicular magnetic recording layer of a magnetic recording disk, the write head comprising:

a slider having a trailing surface and an air-bearing surface (ABS) generally orthogonal to the trailing surface;

a main pole, the main pole comprising a write pole on the trailing surface and having a tip substantially at the ABS and an end recessed from the ABS, an electrically insulating layer formed of a material selected from Al₂O₃, SiC, SiN, diamond-like carbon (DLC), SiO₂ and MgO on the write pole, and a sub pole on the insulating layer and having an end facing the ABS but recessed from the ABS;

an electrically conductive lead connected to the write pole at the end recessed from the ABS;

a return pole magnetically coupled to the sub pole and having an end substantially at the ABS;

an electrically conductive coil between the main pole and the return pole;

a trailing shield substantially at the ABS and magnetically coupled to the return pole; and

a spin torque oscillator (STO) substantially at the recording-layer-facing surface between the trailing shield and the write pole tip;

wherein the return pole, trailing shield, write pole tip, write pole and electrically conductive lead provide an electrically conductive path for current to the STO.

10. The head of claim 9 wherein the sub pole has a thickness greater than the thickness of the write pole.

11. The head of claim 9 wherein the electrically insulating layer has a thickness greater than or equal to 2 nm.

12. The head of claim 9 further comprising a leading shield substantially at the ABS, the write pole tip being located between the leading shield and the trailing shield.