Electroplated Magnetic Film for Read-Write Applications

Abstract

A process is described for the fabrication, through electrodeposition, of Fe x Co y Ni z (x=60-71, y=25-35, z=0-5) films that have, in their as-deposited form, a saturation magnetization of at least 24 kG and a coercivity of less than 0.3 Oe. A key feature is the addition of aryl sulfinates to the plating bath along with a suitable seed layer.

1 . A process for the formation of a magnetic write head that is fully integrated with a magnetic read head that includes a TMJ, comprising:
 forming said read head, including an upper magnetic shield layer;   electrodepositing over said upper magnetic shield a first layer of magnetic material having, as deposited, a saturation magnetization of at least 24kG and a coercivity less than 0.3 Oe;   forming a magnetizing coil over said first layer;   electrodepositing over said first layer a second layer of magnetic material having, as deposited, a saturation magnetization of at least 24 kG and a coercivity less than 0.3 Oe, said first and second layers being magnetically connected at a first end and magnetically separated at a second, opposing, end; and   forming an additional magnetic shield layer over said second layer, thereby completing formation of said magnetic write head without ever subjecting said TMJ read head to a heat treatment.   
     
     
         2 . The process recited in  claim 1  wherein the steps of electrodepositing said first and second magnetic layers further comprise:
 providing a plating bath comprising: 
 
       
         
           
                 
                 
                 
                 
               
                     
                     
                 
                     
                   NiSO 4 •6H 2 O 
                   0-70 
                   g/L 
                 
                     
                   FeSO 4 •7H 2 O 
                   25-120 
                   g/L 
                 
                     
                   CoSO 4 •6H 2 O 
                   10-60 
                   g/L 
                 
                     
                   H 3 BO 3   
                   20-30 
                   g/L 
                 
                     
                   NaCl 
                   0.5-30 
                   g/L 
                 
                     
                   surfactant 
                   0-0.15 
                   g/L, and 
                 
                     
                   Aryl sulfinates 
                   0.05-0.3 
                   g/L; 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
                
                
               
            
           
         
         adjusting said plating bath to have a pH in the range of about 2 to 3; 
         providing an anode selected from the group consisting of Ni and Co; and 
         depositing said layers from said plating bath through the application of asymmetric A.C. under conditions that further comprise:
 a Forward Peak Current Density between about 5 and 30 mA/cm 2 , 
 a Reverse Peak current density of up to about 10 mA/cm 2 , 
 a Forward ON time in the range of from about 5 to 100 ms, 
 a Reverse ON time of up to about 30 ms, and 
 a bath temperature in the range of about 10 to 25% C. 
 
       
     
     
         3 . The process recited in  claim 1  wherein said first and second magnetic layers are deposited on a seed layer of ruthenium. 
     
     
         4 . The process recited in  claim 1  wherein each of said layers of magnetic material has high corrosion resistance, as characterized by a corrosion potential of about −0.18V and an anodic current density of about 10 -5  A/cm 2  at −0.05 volts, in a solution of sodium chloride 
     
     
         5 . The process recited in  claim 1  wherein each of said layers of magnetic material has an internal stress no greater than about 250 MPa.