Head design with low coefficient of thermal expansion insert layer

Abstract

A magnetic read/write head is produced with an insert layer between the substrate and the magnetic transducer. The insert layer has a lower coefficient of thermal expansion than the substrate, which reduces the temperature pole tip recession (T-PTR) of the head because the insert layer is an intervening layer between the substrate and magnetic transducer. The insert layer is produced by plating, e.g., an Invar layer over the substrate prior to fabricating the magnetic transducer. The Invar layer is annealed and the structure planarized prior to depositing a non-magnetic gap layer followed by the fabrication of the magnetic transducer.

1 . A magnetic read/write head comprising: 
 a substrate having a first coefficient of thermal expansion;    a magnetic transducer coupled to the substrate, the magnetic transducer having a second coefficient of thermal expansion that is greater than the first coefficient of thermal expansion;    a conductive layer coupled between the substrate and the magnetic transducer, the conductive layer having a third coefficient of thermal expansion that is less than the first coefficient of thermal expansion; and    a non-magnetic layer coupled between the conductive layer and the magnetic transducer.    
   
   
       2 . The magnetic read/write head of claims  1 , wherein the conductive layer is a layer of plated Invar.  
   
   
       3 . The magnetic read/write head of claims  2 , wherein the plated Invar comprises approximately 34 to 38 percent Nickel and 62 to 66 percent Iron.  
   
   
       4 . The magnetic read/write head of claims  2 , wherein the plated Invar comprises approximately 0.1 to 5.0 percent of Cobalt, 35 to 36 percent of Nickel, and 62 to 64 percent of Iron.  
   
   
       5 . The magnetic read/write head of claims  2 , wherein the plated Invar is annealed at a temperature greater than 450° C.  
   
   
       6 . The magnetic read/write head of claims  1 , wherein the conductive layer coupled between the substrate and the magnetic transducer is between approximately 1.0 μm to 5.0 μm.  
   
   
       7 . The magnetic read/write head of claims  1 , wherein the conductive layer has the approximate dimensions of a bottom shield of the magnetic transducer.  
   
   
       8 . The magnetic read/write head of claims  1 , wherein the non-magnetic layer coupled between the conductive layer and the magnetic transducer comprises at least one of tantalum and SiO 2 .  
   
   
       9 . The magnetic read/write head of claims  8 , wherein the non-magnetic layer is between approximately 0.1 μm and 1.0 μm.  
   
   
       10 . A method of forming a magnetic read/write head, the method comprising: 
 providing a substrate;    plating a NiFe layer over the substrate;    annealing the NiFe layer;    depositing a non-magnetic layer over the NiFe layer; and    producing a magnetic transducer over the non-magnetic layer.    
   
   
       11 . The method of  claim 10 , further comprising depositing an undercoating layer over the substrate prior to plating the NiFe layer.  
   
   
       12 . The method of  claim 11 , further comprising: 
 removing a plating field of the NiFe layer;    depositing a covering layer over the remaining NiFe layer and over the underlying undercoating layer prior to annealing the NiFe layer; and    polishing the covering layer to expose the underlying NiFe layer.    
   
   
       13 . The method of  claim 12 , wherein the remaining NiFe layer has the approximate dimensions of a bottom shield of the magnetic transducer.  
   
   
       14 . The method of  claim 12 , wherein the covering laying and the undercoating layer comprise alumina.  
   
   
       15 . The method of  claim 10 , wherein the NiFe layer is annealed above approximately 450 degrees C.  
   
   
       16 . The method of  claim 15 , wherein the NiFe layer is annealed at approximately 490 degrees C. for approximately 2 hours.  
   
   
       17 . The method of  claim 10 , wherein the NiFe layer is plated at a ratio of approximately 34 to 38 percent Ni and 62 to 66 percent Fe.  
   
   
       18 . The method of  claim 10 , wherein the NiFe layer further includes Co and is plated at a ratio of approximately 0.1 to 5.0 percent of Co, 35 to 36 percent of Ni, and 62 to 64 percent of Fe.  
   
   
       19 . The method of  claim 10 , wherein the NiFe layer is plated to a thickness of approximately 1.0 μm to 5.0 μm.  
   
   
       20 . The method of  claim 10 , wherein the non-magnetic layer comprises at least one of tantalum and SiO 2 .  
   
   
       21 . The method of  claim 20 , wherein the non-magnetic layer is deposited to a thickness of approximately 0.1 μm to 1.0 μm.  
   
   
       22 . The method of  claim 10 , wherein the annealed NiFe layer has a coefficient of thermal expansion that is less than the coefficient of thermal expansion of the substrate.  
   
   
       23 . A method of forming a magnetic read/write head, the method comprising: 
 providing a substrate with a first coefficient of thermal expansion;    plating a conductive layer over the substrate;    annealing the conductive layer, wherein the annealed conductive layer has a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion;    depositing a non-magnetic layer over the conductive layer; and    fabricating a magnetic transducer over the non-magnetic layer, wherein the magnetic transducer has a third coefficient of thermal expansion that is greater than the first coefficient of thermal expansion.