Magnetoresistive sensor fabrication

Abstract

Implementations described and claimed herein include a reader structure, comprising a first reader, including a sensor stack and a top shield structure, the top shield structure comprises a synthetic antiferromagnetic shield (SAF) structure, including a reference layer including at least a layer of NiFe and an impurity additive, an RKKY coupling layer RKKY coupling layer (e.g., Ru layer), and a pinned layer. In another implementation, the RL of the SAF shield structure of a first reader includes at least a layer of amorphous magnetic material. Yet, in another implementation, the SAF shield structure includes an insertion layer of amorphous magnetic material under the SAF shield RL, within the SAF shield RL or between the SAF shield RL and SAF shield Ru.

1 . A reader structure, comprising:
 a first reader, including:
 a sensor stack; and 
 a top shield structure, the top shield structure comprising a synthetic antiferromagnetic shield structure, including:
 a reference layer including at least a layer of NiFe and an impurity additive;
 an RKKY coupling layer; and 
 a pinned layer. 
 
 
   
     
     
         2 . The reader structure of  claim 1 , further comprising a second reader positioned in the down track direction from the first reader, the second reader including:
 a sensor stack; and   a top shield structure, the top shield structure comprising a synthetic antiferromagnetic shield structure, including:
 a reference layer including at least a layer of NiFe and an impurity additive; 
 an RKKY coupling layer; and 
 a pinned layer. 
   
     
     
         3 . The reader structure of  claim 1 , wherein the impurity additive is oxygen. 
     
     
         4 . The reader structure of  claim 1 , wherein the impurity additive is tungsten (W). 
     
     
         5 . The reader structure of  claim 4 , wherein the content of W in the reference layer is less than 14 atomic percent. 
     
     
         6 . The reader structure of  claim 1 , wherein the impurity additive is a refractory material. 
     
     
         7 . The reader structure of  claim 6 , wherein the refractory material is at least one of tantalum, niobium, hafnium, and zirconium. 
     
     
         8 . The reader structure of  claim 1 , wherein the RKKY coupling layer has a thickness in a range of about 0-20 Å. 
     
     
         9 . A reader structure comprising:
 a first reader, including:
 a sensor stack; and 
 a top shield structure, the top shield structure including:
 a synthetic antiferromagnetic (SAF) shield structure, the SAF shield structure including: 
 a reference layer; 
 an insertion layer including at least a layer of amorphous magnetic material, wherein the amorphous magnetic material includes an alloy doped with an amorphous agent, and wherein the amorphous agent is one of tantalum, hafnium, zirconium, and niobium; 
 an RKKY coupling layer; and 
 a pinned layer. 
 
   
     
     
         10 . The reader structure of  claim 9 , further comprising a second reader positioned in the down track direction from the first reader, the second reader including:
 a sensor stack; and   a top shield structure, the top shield structure including:
 a SAF shield structure, the SAF shield structure including:
 a reference layer including at least a layer of NiFe and an impurity additive; 
 an insertion layer including at least a layer of amorphous magnetic material, wherein the amorphous magnetic material includes an alloy with an amorphous agent, and wherein the amorphous agent is one of tantalum, hafnium, zirconium, and niobium; 
 an RKKY coupling layer; and 
 a pinned layer. 
 
   
     
     
         11 . (canceled) 
     
     
         12 . The reader structure of  claim 9 , wherein the alloy is at least one of a nickel alloy, cobalt alloy, and iron alloy. 
     
     
         13 . (canceled) 
     
     
         14 . A reader structure comprising:
 a first reader, including:
 a sensor stack; and 
 a top shield structure, the top shield structure including:
 a synthetic antiferromagnetic structure, including:
 an insertion layer; 
 a reference layer including at least a layer of NiFe and an impurity additive; 
 an RKKY coupling layer; and 
 a pinned layer. 
 
 
   
     
     
         15 . The reader structure of  claim 14 , further comprising a second reader positioned in the down track direction from the first reader, the second reader including:
 a sensor stack; and   a top shield structure, the top shield structure comprising a synthetic antiferromagnetic shield structure, including:
 a reference layer including at least a layer of NiFe and an impurity additive; 
 an RKKY coupling layer; and 
 a pinned layer. 
   
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . The reader structure of  claim 19 , wherein the amorphous material includes at least one of Ta, CoFeB, and CoFeTa. 
     
     
         21 . The reader structure of  claim 9 , wherein the insertion layer is under the reference layer. 
     
     
         22 . The reader structure of  claim 9 , wherein the insertion layer is within the reference layer. 
     
     
         23 . The reader structure of  claim 9 , wherein the insertion layer is between the reference layer and the RKKY coupling layer. 
     
     
         24 . (canceled) 
     
     
         25 . The reader structure of  claim 9 , wherein the alloy includes between approximately 1-30% of the at least one of tantalum, hafnium, zirconium, and niobium. 
     
     
         26 . The reader structure of  claim 9 , wherein the alloy is CoFeTa. 
     
     
         27 . The reader structure of  claim 26 , wherein the CoFeTa includes approximately 6-20% Ta.