Bottom shield stabilized magnetic seed layer

Abstract

A data reader generally capable of sensing data bits may be configured at least with a magnetic stack that has free and fixed magnetization structures atop a magnetic seed layer. A bottom shield may be positioned contactingly adjacent the magnetic stack opposite a top shield with the bottom shield having a fixed pinning magnetization set to a predetermined magnetic orientation.

What is claimed is: 
     
         1 . An apparatus comprising:
 a magnetic stack comprising free and fixed magnetization structures atop a magnetic seed layer; and   a bottom shield contactingly adjacent the magnetic stack opposite a top shield, the bottom shield comprising a fixed pinning magnetization set to a predetermined magnetic orientation.   
     
     
         2 . The apparatus of  claim 1 , wherein the fixed magnetization structure of the magnetic stack comprises a synthetic antiferromagnet (SAF). 
     
     
         3 . The apparatus of  claim 2 , wherein an antiferromagnet (AFM) is disposed between the magnetic seed and the fixed magnetization structure of the magnetic stack. 
     
     
         4 . The apparatus of  claim 1 , wherein the fixed pinning magnetization is set by a synthetic antiferromagnet (SAF) in the bottom shield. 
     
     
         5 . The apparatus of  claim 4 , wherein an antiferromagnet (AFM) is disposed between the SAF and a shield seed layer in the bottom shield. 
     
     
         6 . The apparatus of  claim 5 , wherein the shield seed layer has a predetermined texture corresponding to the predetermined magnetic orientation. 
     
     
         7 . The apparatus of  claim 1 , wherein the bottom shield has a wider width at an air bearing surface (ABS) than an average width of the magnetic stack. 
     
     
         8 . The apparatus of  claim 1 , wherein the predetermined magnetic orientation is parallel to an air bearing surface (ABS). 
     
     
         9 . The apparatus of  claim 1 , wherein the magnetic stack is disposed between side shields. 
     
     
         10 . The apparatus of  claim 9 , wherein the each side shield is separated from the magnetic stack by an insulating layer. 
     
     
         11 . The apparatus of  claim 10 , wherein each insulating layer continuously extends to separate the side shield from the bottom shield. 
     
     
         12 . The apparatus of  claim 9 , wherein each side shield continuously extends from the free magnetization structure of the magnetic stack to the top shield. 
     
     
         13 . A data reader comprising:
 a magnetic stack comprising free and fixed magnetization structures atop a magnetic seed layer; and   a bottom shield contactingly adjacent and coupled to the magnetic stack opposite a top shield, the bottom shield comprising a fixed pinning magnetization set to a predetermined magnetic orientation.   
     
     
         14 . The data reader of  claim 13 , wherein the bottom shield is coupled to the magnetic seed layer of the magnetic stack. 
     
     
         15 . The data reader of  claim 13 , wherein the predetermined magnetic orientation matches a fixed magnetization orientation of the fixed magnetization structure of the magnetic stack. 
     
     
         16 . The data reader of  claim 13 , wherein the magnetic seed of the magnetic stack contacts a first ferromagnetic layer of the bottom layer, the first ferromagnetic layer separated from a second ferromagnetic layer by a non-magnetic spacer layer as part of a synthetic antiferromagnet (SAF). 
     
     
         17 . A method comprising:
 forming a magnetic stack comprising free and fixed magnetization structures atop a magnetic seed layer;   contact the magnetic stack with a bottom shield opposite a top shield, the bottom shield comprising a fixed pinning magnetization set to a predetermined magnetic orientation.   
     
     
         18 . The method of  claim 18 , wherein the magnetic stack exclusively undergoes a first annealing operation. 
     
     
         19 . The method of  claim 18 , wherein the predetermined magnetic orientation is provided by a second annealing operation conducted on the bottom shield and magnetic stack subsequent to the first annealing operation. 
     
     
         20 . The method of  claim 19 , wherein the first and second annealing operations configure the fixed pinning magnetizations to different, orthogonal orientations.