Multi-read sensor having a narrow read gap structure

Abstract

In one embodiment, a magnetic head includes at least one magnetoresistive (MR) element positioned at a media-facing surface of the magnetic head, a lower portion of the at least one MR element extending in an element height direction away from the media-facing surface of the magnetic head farther than an upper portion of the at least one MR element, at least one back wiring layer positioned behind the upper portion of the at least one MR element in the element height direction and above the lower portion of the at least one MR element, the at least one back wiring layer being configured to electrically communicate with the at least one MR element, and an upper wiring layer positioned above the at least one 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.

What is claimed is: 
     
         1 . A magnetic head, comprising:
 at least one magnetoresistive (MR) element, the at least one MR element extending in an element height direction away from a media-facing surface of the magnetic head; and   at least one back wiring layer positioned above at least one lower layer of the at least one MR element at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the at least one back wiring layer is configured to electrically communicate with the at least one MR element.   
     
     
         2 . The magnetic head as recited in  claim 1 , wherein each of the at least one MR element comprises a pinned layer, a barrier layer positioned above the pinned layer, and a free layer positioned above the barrier layer, and wherein the at least one back wiring layer is configured to separately extract a signal from its respective MR element during a read operation. 
     
     
         3 . The magnetic head as recited in  claim 1 , wherein the magnetic head comprises a plurality of MR elements. 
     
     
         4 . The magnetic head as recited in  claim 1 , further comprising:
 a lower shield layer positioned below the at least one MR element at a media-facing surface of the magnetic head; and   an upper shield layer positioned above the at least one MR element, the upper shield layer being configured to electrically communicate with the at least one MR element.   
     
     
         5 . The magnetic head as recited in  claim 4 , further comprising an insulating layer positioned between the lower shield layer and the at least one MR element, wherein the upper shield layer is configured to act as an upper electrode for the at least one MR element. 
     
     
         6 . The magnetic head as recited in  claim 5 , further comprising a magnetic domain control layer positioned on both sides of each of the at least one MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each of the at least one MR element by an insulating layer. 
     
     
         7 . The magnetic head as recited in  claim 5 , further comprising an insulating layer positioned between the upper shield layer and the back wiring layer, wherein a portion of each of the at least one 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. 
     
     
         8 . The magnetic head as recited in  claim 5 , further comprising a wiring underlayer positioned below each of the at least one 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. 
     
     
         9 . The magnetic head as recited in  claim 4 , further comprising an upper wiring layer positioned above each of the at least one 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, 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 one MR element. 
     
     
         10 . The magnetic head as recited in  claim 9 , further comprising a magnetic domain control layer positioned on both sides of each of the at least one MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each of the at least one 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 of the at least one MR element in a cross-track direction, wherein the magnetic side shield layer is separated from each of the at least one 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:
 at least one magnetoresistive (MR) element positioned at a media-facing surface of the magnetic head, a lower portion of the at least one MR element extending in an element height direction away from the media-facing surface of the magnetic head farther than an upper portion of the at least one MR element;   at least one back wiring layer positioned behind the upper portion of the at least one MR element in the element height direction and above the lower portion of the at least one MR element, wherein the at least one back wiring layer is configured to electrically communicate with the at least one MR element; and   an upper wiring layer positioned above the at least one 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.   
     
     
         14 . The magnetic head as recited in  claim 13 , wherein each of the at least one MR element comprises a pinned layer, a barrier layer positioned above the pinned layer, and a free layer positioned above the barrier layer, wherein the upper portion of each of the at least one MR element comprises at least the free layer, and wherein the at least one back wiring layer is configured to separately extract a signal from its respective MR element during a read operation. 
     
     
         15 . A method for forming a magnetic head, the method comprising:
 forming at least one magnetoresistive (MR) element, the at least one MR element extending in an element height direction away from a media-facing surface of the magnetic head; and   forming at least one back wiring layer positioned above at least one lower layer of the at least one MR element at a position away from the media-facing surface of the magnetic head in the element height direction, wherein the at least one back wiring layer is configured to electrically communicate with the at least one MR element.   
     
     
         16 . The method as recited in  claim 15 , further comprising:
 forming a lower shield layer below the at least one MR element; and   forming an upper shield layer above the at least one MR element, the upper shield layer being configured to electrically communicate with the at least one MR element,   wherein forming the at least one MR element further comprises, for each of the at least one MR element:
 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 to sense data on a magnetic medium passed across the media-facing surface of the magnetic head, and 
 wherein the at least one back wiring layer is configured to separately extract a signal from its respective MR element during a read operation. 
   
     
     
         17 . The method as recited in  claim 16 , further comprising forming an insulating layer between the lower shield layer and the at least one MR element, wherein a portion of each of the one 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. 
     
     
         18 . The method as recited in  claim 17 , further comprising forming a magnetic domain control layer on both sides of each of the one MR element in a cross-track direction, wherein the magnetic domain control layer is separated from each of the one MR element by an insulating layer. 
     
     
         19 . The method as recited in  claim 16 , further comprising forming an insulating layer between the upper shield layer and the at least one back wiring layer. 
     
     
         20 . The method as recited in  claim 15 , further comprising forming a wiring underlayer below the at least one MR element, the wiring underlayer being configured to act as a lower electrode for the at least one MR element, wherein the wiring underlayer comprises Cr, NiFe, and/or CoFe.