Planar design for sensors in a dual free layer read head

Patent metadata

Field	Value
Publication number	US-11514934-B1
Application number	US-202117512216-A
Country	US
Kind code	B1
Filing date	Oct 27, 2021
Priority date	Oct 27, 2021
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

The present disclosure generally relates to a dual free layer (DFL) two dimensional magnetic recording (TDMR) read head. The read head comprises a first sensor, a first rear hard bias (RHB) structure disposed adjacent to the first sensor, an upper shield disposed over the first sensor and first RHB structure, a lower shield disposed over the upper shield, a second sensor disposed over the lower shield, and a second RHB structure disposed adjacent to the second sensor. A first surface of the first sensor is substantially flush or aligned with a first surface of the first RHB structure. A first surface of the second sensor is substantially flush or aligned with a first surface of the second RHB structure. The upper shield extends linearly from a media facing surface into the read head. The first lower shield is over-milled a greater amount of time than the second lower shield.

First claim

What is claimed is:

1. A read head, comprising:
a first lower shield;
a first upper shield over the first lower shield;
a first sensor disposed at a media facing surface (MFS) between the first lower shield and the first upper shield, the first sensor comprising a first surface disposed adjacent to the first upper shield;
a first rear hard bias (RHB) structure disposed adjacent to the first sensor between the first lower shield and the first upper shield, the first RHB structure being recessed from the MFS and recessed into the first lower shield, wherein a first surface of the first RHB structure is substantially aligned with the first surface of the first sensor;
a second lower shield disposed over the first upper shield;
a second sensor disposed at the MFS between the second lower shield and a second upper shield, the second sensor comprising a first surface disposed adjacent to the second lower shield; and
a second RHB structure disposed adjacent to the second sensor adjacent to the second lower shield, the second RHB structure being recessed from the MFS, wherein a first surface of the second RHB structure is substantially aligned with the first surface of the second sensor.

2. The read head of claim 1 , wherein the first RHB structure is recessed into the first lower shield a distance of about 15 nm to about 20 nm.

3. The read head of claim 1 , wherein a down-track spacing between the first sensor and the second sensor is between about 75 nm to about 85 nm.

4. The read head of claim 1 , wherein the first upper shield extends substantially linearly from the MFS into the read head.

5. The read head of claim 1 , further comprising:
a first insulation layer surrounding a second surface and a third surface of the first RHB structure;
a second insulation layer surrounding a second surface and the first surface of the second RHB structure; and
a read separation gap disposed between the first upper shield and the second lower shield.

6. The read head of claim 5 , wherein a first surface of the first insulation layer disposed adjacent to the first upper shield is substantially aligned with the first surface of the first sensor and the first surface of the first RHB structure.

7. The read head of claim 5 , wherein the second lower shield comprises a first portion disposed at the MFS having a first thickness of about 20 nm to about 30 nm and a second portion disposed between the second RHB structure and the second insulation layer having a second thickness of about 15 nm to about 20 nm.

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

9. A read head, comprising:
a first lower shield;
a first sensor disposed at a media facing surface (MFS) on the first lower shield;
a first rear hard bias (RHB) structure disposed adjacent to the first sensor, the first RHB structure being recessed from the MFS and recessed into the first lower shield;
a first upper shield over the first sensor and the first RHB structure, the first upper shield extending substantially linearly from the MFS into the read head;
a read separation gap disposed over the first upper shield, the read separation gap extending substantially linearly from the MFS into the read head;
a second lower shield disposed over the read separation gap;
a second sensor disposed at the MFS on the second lower shield;
a second RHB structure disposed adjacent to the second sensor, the second RHB structure being recessed from the MFS; and
a second upper shield over the second sensor and the second RHB structure.

10. The read head of claim 9 , wherein the first sensor comprises a first surface disposed adjacent to the first upper shield, wherein the first RHB structure comprises a first surface disposed adjacent to the first upper shield, and wherein the first surface of the first sensor is substantially aligned with the first surface of the first RHB structure.

11. The read head of claim 9 , wherein the second sensor comprises a first surface disposed adjacent to the second lower shield, wherein the second RHB structure comprises a first surface disposed adjacent to the second lower shield, and wherein the first surface of the second sensor is substantially aligned with the first surface of the second RHB structure.

12. The read head of claim 9 , wherein the first sensor is over-milled a greater amount of time than the second sensor, and wherein the first RHB structure is disposed lower with respect to the first sensor than the second RHB structure is disposed with respect to the second sensor.

13. The read head of claim 9 , wherein the first sensor and the second sensor are physically asymmetric.

14. A magnetic recording device comprising the read head of claim 9 .

15. A read head, comprising:
a first lower shield;
a first upper shield over the first lower shield;
a first dual free layer (DFL) sensor disposed at a media facing surface (MFS) between the first lower shield and the first upper shield, the first sensor comprising a first surface disposed adjacent to the first upper shield;
a first rear hard bias (RHB) structure disposed adjacent to the first sensor between the first lower shield and the first upper shield, the first RHB structure being recessed from the MFS and recessed into the first lower shield, wherein a first surface of the first RHB structure is substantially aligned with the first surface of the first sensor;
a read separation gap disposed over the first upper shield, the read separation gap extending substantially linearly from the MFS into the read head;
a second lower shield disposed over the read separation gap;
a second DFL sensor disposed at the MFS on the second lower shield; and
a second RHB structure disposed adjacent to the second sensor, the second RHB structure being recessed from the MFS, wherein a down-track spacing between the first sensor and the second sensor is between about 75 nm to about 85 nm.

16. The read head of claim 15 , wherein the second DFL sensor comprises a first surface disposed adjacent to the second lower shield and the second RHB structure comprises a second surface disposed adjacent to the second lower shield, and wherein the second surface of the second RHB structure is substantially aligned with the first surface of the second DFL sensor.

17. The read head of claim 15 , further comprising:
a first anti-ferromagnetic coupling (AFC) soft bias shield disposed adjacent to the first DFL sensor at the MFS between the first lower shield and the first upper shield; and
a second AFC soft bias shield disposed adjacent to the second DFL sensor at the MFS between the second lower shield and the second upper shield.

18. The read head of claim 17 , further comprising:
a first insulation layer disposed between the first DFL sensor and the first AFC soft bias shield at the MFS; and
a second insulation layer disposed between the second DFL sensor and the second AFC soft bias shield at the MFS.

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

20. A read head, comprising:
a first lower shield;
a first sensor disposed at a media facing surface (MFS) on the first lower shield;
a first rear hard bias (RHB) structure disposed adjacent to the first sensor, the first RHB structure being recessed from the MFS;
a first upper shield over the first sensor and the first RHB structure, the first upper shield extending substantially linearly from the MFS into the read head;
a read separation gap disposed over the first upper shield, the read separation gap extending s

Assignees

• Western Digital Tech Inc

Inventors

• Mao Ming
• Chien Chen-Jung
• Mauri Daniele
• Baião De Albuquerque Goncalo Marcos
• Hu Chih-Ching
• Roy Anup Ghosh
• Wang Yung-Hung

Classifications

• G11B5/11

  Shielding of head against electric or magnetic fields · CPC title

• G11B5/3932 Primary

  Magnetic biasing films · CPC title

• G11B2005/3996

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

• G11B5/3912 Primary

  Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields (G11B5/3916 takes precedence) · CPC title

• G11B5/399

  with intrinsic biasing, e.g. provided by equipotential strips · CPC title