DFL TDMR middle shield throat height control for improved stability

Patent metadata

Field	Value
Publication number	US-12437780-B2
Application number	US-202318243053-A
Country	US
Kind code	B2
Filing date	Sep 6, 2023
Priority date	Sep 6, 2023
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

The present disclosure generally relates to a dual free layer two dimensional magnetic recording read head. The read head comprises a lower shield, a first sensor disposed over the first lower shield, a first rear hard bias (RHB) structure recessed from a media facing surface (MFS), a first upper shield disposed over the first sensor, a middle shield disposed over the first sensor at the MFS, a second sensor disposed over the middle shield, a second RHB structure recessed from the MFS, and an upper shield disposed over the second sensor. The middle shield has a U-like shape and a ratio of a width to a throat height of 6:1, where the throat height is less than or equal to about 2 μm. The first and second RHB structures each individually has a stripe height about 3 times greater than a stripe height of the middle shield.

First claim

What is claimed is:

1. A read head, comprising:
a lower shield;
a first sensor disposed over the lower shield;
a first upper shield disposed over the first sensor;
a middle shield disposed over the first upper shield, the middle shield comprising a first portion disposed at a media facing surface, a first leg coupled to the first portion, and a second leg coupled to the first portion, wherein a ratio of a width to a throat height of the middle shield is 6:1 or greater, the throat height being defined by a thickness of the first portion from the media facing surface;
a second sensor disposed over the middle shield, wherein the first sensor and the second sensor each individually comprises a first free layer and a second free layer; and
a second upper shield disposed over the second sensor.

2. The read head of claim 1 , wherein the throat height of the middle shield is less than or equal to about 2 μm.

3. The read head of claim 1 , wherein the first portion, the first leg, and the second leg form a U-like shape.

4. The read head of claim 3 , further comprising an insulating material disposed between the first leg and the second leg.

5. The read head of claim 1 , wherein the first leg and the second leg each individually has a height of about 4 μm and a width of about 1 μm.

6. A magnetic recording device comprising the read head of claim 1 .

7. A read head comprising:
a lower shield;
a first sensor disposed over the lower shield at a media facing surface (MFS), the first sensor comprising a first free layer and a second free layer;
a first rear hard bias (RHB) structure recessed from the MFS by the first sensor;
a first upper shield disposed over the first sensor;
a middle shield disposed over the first upper shield, wherein the first RHB has a stripe height about 3 times greater than a stripe height of the middle shield;
a second sensor disposed over the middle shield;
a second RHB structure recessed from the MFS by the second sensor, the second RHB having a stripe height about 3 times greater than the stripe height of the middle shield; and
a second upper shield disposed over the second sensor.

8. The read head of claim 7 , wherein the middle shield has a throat height less than or equal to about 2 μm.

9. The read head of claim 7 , wherein the middle shield comprises a first portion disposed at the media facing surface, a first leg coupled to the first portion, and a second leg coupled to the first portion, wherein a ratio of a width to a throat height of the middle shield is 6:1 or greater, the throat height being defined by a thickness of the first portion from the media facing surface.

10. The read head of claim 7 , wherein the second upper shield has a stripe height greater than the stripe height of the second RHB structure.

11. The read head of claim 7 , wherein a stripe height of the second upper shield is about 10 μm.

12. The read head of claim 11 , wherein a stripe height of the lower shield is equal to the stripe height of the second upper shield.

13. A magnetic recording device comprising the read head of claim 7 .

14. A dual free layer (DFL) two dimensional magnetic recording (TDMR) read head, comprising:
a lower shield;
a first sensor disposed over the lower shield at a media facing surface (MFS), the first sensor comprising a first free layer and a second free layer;
a first rear hard bias (RHB) structure recessed from the MFS by the first sensor;
a first upper shield disposed over the first sensor;
a middle shield disposed over the first upper shield, the middle shield comprising a first portion disposed at the MFS, a first leg coupled to the first portion, and a second leg coupled to the first portion, wherein the middle shield has a throat height less than or equal to about 2 μm, the throat height being defined by a thickness of the first portion from the MFS;
a second sensor disposed over the middle shield, the second sensor comprising a first free layer and a second free layer;
a second RHB structure recessed from the MFS by the second sensor, the second RHB having a stripe height greater than a stripe height of the middle shield; and
a second upper shield disposed over the second sensor, the second upper shield having a stripe height greater than the second RHB structure.

15. The DFL TDMR read head of claim 14 , wherein a ratio of a width to the throat height of the middle shield is 6:1 or greater.

16. The DFL TDMR read head of claim 14 , wherein the first RHB structure has a stripe height greater than the middle shield, and wherein the lower shield has a stripe height greater than the first RHB structure.

17. The DFL TDMR read head of claim 14 , wherein the first RHB structure and the second RHB each individually has a stripe height about 3 times greater than the stripe height of the middle shield.

18. The DFL TDMR read head of claim 14 , wherein the first portion, the first leg, and the second leg form a U-like shape, and wherein an insulating material is disposed between the first leg and the second leg.

19. A magnetic recording device comprising the DFL TDMR read head of claim 15 .

Assignees

• Western Digital Tech Inc

Inventors

• Liu Xiaoyong
• Li Zhanjie
• Wei Yaguang
• Okada Yukimasa
• Baião De Albuquerque Goncalo Marcos

Classifications

• G11B5/398

  Specially shaped layers · CPC title

• G11B5/3932

  Magnetic biasing films · CPC title

• G11B2005/3996

  large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices · CPC title

• G11B5/3954 Primary

  the active elements transducing on a single track · CPC title

• G11B5/3909

  Arrangements using a magnetic tunnel junction · CPC title