DFL TDMR middle shield throat height control for improved stability
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.
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 .