Thin film magnetic alloy having low noise, high coercivity and high squareness

Abstract

A Co-Pt based magnetic alloy which has been doped with a relatively high amount of nitrogen, e.g., or above 1 at. % is obtained having high coercivity, for example in the range of 1400 Oe or above, and an increased signal-to-noise ratio as compared to the same Co-Pt based alloy which has not been doped with nitrogen. The alloy is vacuum deposited, for example, by sputtering, and the nitrogen may be introduced from the sputtering gas or from the sputtering target. Other low-solubility elements providing the grain uniformity and isolation include: B, P, S, C, Si, As, Se and Te.

What is claimed is:  
     
       1. A method of forming a low noise magnetic thin film recording media, comprising the steps of: 
       providing a substrate;  
       vacuum depositing a magnetic layer exhibiting ferromagnetism as deposited over said substrate, said magnetic layer comprising cobalt and platinum, said magnetic layer being doped with nitrogen in an amount greater than approximately 1 atomic percent, the magnetic layer doped with nitrogen exhibiting a higher signal-to-noise ratio than the magnetic layer not doped with nitrogen.  
     
     
       2. A method of forming a low noise magnetic thin film recording media, comprising the steps of: 
       providing a substrate;  
       sputter depositing onto said substrate a nucleation layer; and  
       vacuum depositing a magnetic layer exhibiting ferromagnetism as deposited onto said nucleation layer, said magnetic layer comprising cobalt and platinum, said magnetic layer being doped with nitrogen in an amount greater than approximately 1 atomic percent, the magnetic layer doped with nitrogen exhibiting a higher signal-to-noise ratio than the magnetic layer not doped with nitrogen.  
     
     
       3. The method of  claim 2 , wherein said step vacuum depositing comprises sputtering in a sputtering apparatus, and wherein said nitrogen is introduced into said magnetic layer from its gaseous state within a chamber of said sputtering apparatus. 
     
     
       4. The method of  claim 2 , wherein said magnetic layer further comprises at least one additional element selected from the group consisting of Ta, Ti, Ni, Cr, and B. 
     
     
       5. The method of  claim 2 , wherein said step of vacuum deposition comprises sputtering elements from a sputtering target, and wherein the source of said nitrogen in said magnetic layer is at least in substantial part said sputtering target. 
     
     
       6. The method of  claim 4 , wherein said step of vacuum depositing comprises sputtering elements from a sputtering target, and wherein the source of said nitrogen in said magnetic layer is at least in substantial part said sputtering target. 
     
     
       7. The method of  claim 5 , wherein said source of nitrogen in said sputtering target comprises a nitride of at least one element selected from the group consisting of Co, Pt, Ta, Ti, Ni, Cr, and B. 
     
     
       8. The method of  claim 2 , wherein the step of sputter depositing said nucleation layer comprises the step of sputter depositing NiP with P about 15 wt. % together with up to 5 wt. % an oxide of at least one element selected from the group consisting of Al, Ti, Ta, Zr and Hf. 
     
     
       9. In a method for fabricating a low noise thin film magnetic recording media of the type having a magnetic layer exhibiting ferromagnetism as deposited, said magnetic layer comprising cobalt and platinum, and wherein the magnetic layer is formed by sputter deposition, an improvement comprising the steps of: 
       introducing at least one additional element into said magnetic layer during deposition of the cobalt and platinum, said at least one additional element selected from the group consisting of Ta, Ti, Ni, Cr, and B; and  
       introducing nitrogen into the sputtering atmosphere during the deposition of the magnetic layer in an amount sufficient to incorporate the nitrogen into the magnetic layer in an amount greater than 1 atomic percent.  
     
     
       10. A method of forming a low noise magnetic thin film recording media, comprising the steps of: 
       providing a substrate;  
       sputtering onto said substrate a nucleation layer; and  
       vacuum depositing a magnetic layer on said nucleation layer, said magnetic layer comprising cobalt, platinum, nickel, and said magnetic layer further being doped with at least one element selected from the group consisting of: B, P, S, C, Si, As, Se and Te.  
     
     
       11. The method of  claim 1  wherein said magnetic layer further comprises at least one material selected from the group consisting of tantalum and titanium. 
     
     
       12. The method of  claim 11  wherein said at least one additional material comprises less than or equal to 10 atomic percent of said magnetic layer. 
     
     
       13. The method of  claim 11  wherein said magnetic layer further comprises boron. 
     
     
       14. The method of  claim 13  wherein said magnetic layer further comprises chromium. 
     
     
       15. The method of  claim 13  wherein said boron comprises less than or equal to 3 atomic percent and said chromium comprises less than or equal to 6 atomic percent of said magnetic layer. 
     
     
       16. The method of  claim 15  wherein the combined atomic percentage of tantalum, titanium, chromium and boron is less than or equal to 20 atomic percent. 
     
     
       17. The method of  claim 8  wherein said oxide comprises Al 2 O 3 . 
     
     
       18. A method of forming a low noise magnetic thin film recording media, comprising the steps of: 
       
         providing a substrate;  
       
       
         vacuum depositing a magnetic layer on said substrate, said magnetic layer comprising cobalt, platinum, at least one element selected from the group consisting of B, P, S, C, Si, As, Se and Te, and at least one element selected from the group consisting of tantalum and titanium.  
       
     
     
       19. Method of  claim 18  wherein said at least one element selected from the group consisting of tantalum and titanium comprises less than or equal to  10  atomic percent of said magnetic layer.  
     
     
       20. Method of  claim 18  wherein said magnetic layer comprises boron.  
     
     
       21. Method of  claim 20  wherein said boron comprises less than about  6  atomic percent of said magnetic layer.  
     
     
       22. Method of  claim 20  wherein said magnetic layer comprises chromium.  
     
     
       23. Method of  claim 22  wherein the combined atomic percentage of tantalum, titanium, chromium and boron is less than or equal to  20  atomic percent.  
     
     
       24. Method of  claim 18  further comprising: 
       
         sputtering a nucleation layer onto said substrate prior to said vacuum depositing a magnetic layer, wherein said vacuum depositing a magnetic layer comprises vacuum depositing said magnetic layer onto said nucleation layer.  
       
     
     
       25. Method of  claim 26  wherein said nucleation layer comprises nickel and phosphorus.  
     
     
       26. Method of  claim 18  wherein said vacuum depositing comprises sputtering.