Multi-read sensor having a narrow read gap structure

1. A magnetic head, comprising:

a lower shield layer positioned at a media-facing surface of the magnetic head;

at least two magnetoresistive (MR) elements positioned above the lower shield layer, each MR element extending in an element height direction away from the media-facing surface of the magnetic head;

back wiring layers positioned above at least one lower layer of each of the MR elements at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the back wiring layers are configured to electrically communicate with the MR elements and configured to separately extract signals from each MR element during a read operation; and

an upper shield layer positioned above the MR elements that is configured to electrically communicate with the MR elements.

2. The magnetic head as recited in claim 1 , wherein each MR element comprises a pinned layer, a barrier layer positioned above the pinned layer, and a free layer positioned above the barrier layer.

3. The magnetic head as recited in claim 2 , further comprising at least four MR elements.

4. The magnetic head as recited in claim 1 , further comprising an insulating layer positioned between the lower shield layer and the MR elements, wherein the upper shield layer is configured to act as an upper electrode for the MR elements.

5. The magnetic head as recited in claim 4 , further comprising a magnetic domain control layer positioned on both sides of each MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each MR element by an insulating layer.

6. The magnetic head as recited in claim 4 , further comprising an insulating layer positioned between the upper shield layer and the back wiring layer, wherein a portion of each MR element which extends away from the media-facing surface of the magnetic head in the element height direction is configured to act as a lower electrode for its respective MR element.

7. The magnetic head as recited in claim 4 , further comprising a wiring underlayer positioned below each MR element, the wiring underlayer being configured to act as a lower electrode for its respective MR element.

8. The magnetic head as recited in claim 7 , wherein the wiring underlayer comprises Cr, NiFe, and/or CoFe.

9. The magnetic head as recited in claim 1 , further comprising an upper wiring layer positioned above each MR element at the media-facing surface and extending in the element height direction away from the media-facing surface, wherein the upper wiring layer is configured to electrically communicate with the back wiring layer, and wherein the lower shield layer is configured to act as a lower electrode for the MR elements.

10. The magnetic head as recited in claim 9 , further comprising a magnetic domain control layer positioned on both sides of each MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each MR element by an insulating layer.

11. The magnetic head as recited in claim 9 , further comprising a magnetic side shield layer positioned on both sides of each MR element in a cross-track direction, wherein the magnetic side shield layer is separated from each MR element by an insulating layer.

12. A magnetic data storage system, comprising:

at least one magnetic head as recited in claim 1 ;

a magnetic medium;

a drive mechanism for passing the magnetic medium over the at least one magnetic head; and

a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.

13. A magnetic head, comprising:

a lower shield layer positioned at a media-facing surface of the magnetic head;

at least two magnetoresistive (MR) elements positioned above the lower shield layer, each MR element extending in an element height direction away from the media-facing surface of the magnetic head;

back wiring layers positioned above at least one lower layer of each of the MR elements at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the back wiring layers are configured to electrically communicate with the MR elements and configured to separately extract signals from each MR element during a read operation; and

an upper wiring layer positioned above each MR element at the media-facing surface of the magnetic head and extending in the element height direction away from the media-facing surface of the magnetic head, the upper wiring layer being configured to electrically communicate with the back wiring layer,

wherein the upper wiring layer is configured to act as an upper electrode for the MR elements, and

wherein the lower shield layer is configured to act as a lower electrode for the MR elements.

14. A method for forming a magnetic head, the method comprising:

forming a lower shield layer;

forming at least two magnetoresistive (MR) elements positioned above the lower shield layer at a media-facing surface of the magnetic head, each MR element extending in an element height direction away from the media-facing surface of the magnetic head;

forming a back wiring layer positioned above the at least two MR elements at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the back wiring layer is configured to electrically communicate with the at least two MR elements and configured to separately extract signals from each MR element during a read operation; and

forming an upper shield layer positioned above the at least two MR elements and configured to electrically communicate with the at least two MR elements, wherein the upper shield layer is configured to act as an upper electrode for the at least two MR elements.

15. The method as recited in claim 14 , wherein forming the at least two MR elements further comprises:

forming a pinned layer;

forming a barrier layer above the pinned layer; and

forming a free layer above the barrier layer, the free layer being configured for sensing data on a magnetic medium passed across the media-facing surface of the magnetic head.

16. The method as recited in claim 14 , further comprising forming an insulating layer between the lower shield layer and the at least two MR elements, wherein a portion of each MR element which extends away from the media-facing surface of the magnetic head is configured to act as a lower electrode for its respective MR element.

17. The method as recited in claim 16 , further comprising forming a magnetic domain control layer on both sides of each MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each MR element by an insulating layer.

18. The method as recited in claim 16 , further comprising forming an insulating layer between the upper shield layer and the back wiring layer.

19. The method as recited in claim 16 , further comprising forming a wiring underlayer below each MR element, the wiring underlayer being configured to act as a lower electrode for its respective MR element, wherein the wiring underlayer comprises Cr, NiFe, and/or CoFe.

20. The method as recited in claim 14 , further comprising:

forming an upper wiring layer above each MR element at the media-facing surface and extending in the element height direction away from the media-facing surface,

wherein the upper wiring layer is configured to electrically communicate with the back wiring layer, and

wherein the lower shield layer is configured to act as a lower electrode for the at least two MR elements; and

forming at least one of a magnetic domain control layer and a magnetic side shield layer on both sides of each MR element in a cross-track direction,

wherein the magnetic domain control layer and/or the magnetic side shield layer is separated from each MR element by an insulating layer.