Method of producing a magnetic recording medium and a magnetic recording medium formed thereby

Abstract

A perpendicular magnetic recording medium has a magnetic recording layer with ferromagnetic crystalline grains and nonmagnetic and nonmetallic grain boundary region surrounding the grains. The surface of its underlayer, before forming the magnetic recording layer, is exposed to an O 2 or N 2 atmosphere or an atmosphere of rare gas and O 2 or N 2 , to attach the O 2 or N 2 as nucleation sites for promoting growth of the nonmagnetic and nonmetallic region. By forming the magnetic recording layer thereafter, both ferromagnetic crystalline grains and the nonmagnetic and nonmetallic grain boundary region are formed from the initial stage of the growth of the magnetic recording layer. Thus, a magnetic recording layer having excellent segregation structure can be formed.

1 . A method of producing a perpendicular magnetic recording medium comprising the steps of: 
 forming an underlayer over a nonmagnetic substrate:    exposing the underlayer in an atmosphere containing °  2  or N 2  after the underlayer has been fully formed: and then    forming a magnetic recording layer on the exposed underlayer,    wherein the magnetic recording layer comprises ferromagnetic crystalline grains and nonmagnetic grain boundary region composed mainly of oxide or nitride surrounding the crystalline grains.    
     
     
         2 . A method of producing a perpendicular magnetic recording medium according to  claim 1 , 
 wherein the magnetic recording layer is deposited using a target composed of an oxide or a nitride.    
     
     
         3 . A method of producing a perpendicular magnetic recording medium according to  claim 1 , 
 wherein the magnetic recording layer is deposited using a target composed of an oxide or a nitride of an element selected from Cr, Co, Si, Al, Ti, Ta, Hf, Zr, Y, and Ce.    
     
     
         4 . A method of producing a perpendicular magnetic recording medium according to  claim 1 , 
 wherein the ferromagnetic crystalline grains are composed of a CoPt alloy, an FePt alloy, or one of these alloys that contains additive element selected from Cr, Ni, Nb, Ta, and B,    the nonmagnetic grain boundary region is composed of an oxide or a nitride of an element selected from Cr, Co, Si, Al, Ti, Ta, Hf, Zr, Y, and Ce, and    the ferromagnetic crystalline grains exhibit magnetic anisotropy perpendicular to the film surface.    
     
     
         5 . A method of producing a perpendicular magnetic recording medium according to  claim 4 , 
 wherein the magnetic recording medium is deposited using a target composed of an alloy and one of an oxide or a nitride, wherein the alloy is a CoPt alloy, an FePt alloy, or one of these alloys that contains additive element(s) selected from Cr, Ni, Nb, Ta, and B, and the oxide or the nitride is that of an element selected from Cr, Co, Si, Al, Ti, Ta, Hf, Zr, Y, and Ce.    
     
     
         6 . A method of producing a perpendicular magnetic recording medium according to  claim 1 , wherein the underlayer is composed of Ru or a Ru alloy.  
     
     
         7 . A method of producing a perpendicular magnetic recording medium according to  claim 6 , wherein the Ru alloy is RuW, RuCu, RuC, RuB, or RuCoCr.  
     
     
         8 . A method of producing a perpendicular magnetic recording medium according to  claim 4 , wherein the underlayer is composed of Ru or a Ru alloy.  
     
     
         9 . A method of producing a perpendicular magnetic recording medium according to  claim 8 , wherein the Ru alloy is RuW, RuCu, RuC, RuB, or RuCoCr.  
     
     
         10 . A perpendicular magnetic recording medium produced by the method according to  claim 1 .  
     
     
         11 . A perpendicular magnetic recording medium produced by the method according to  claim 2 .  
     
     
         12 . A perpendicular magnetic recording medium produced by the method according to  claim 3 .  
     
     
         13 . A perpendicular magnetic recording medium produced by the method according to  claim 4 .  
     
     
         14 . A perpendicular magnetic recording medium produced by the method according to  claim 5 .  
     
     
         15 . A perpendicular magnetic recording medium produced by the method according to  claim 6 .  
     
     
         16 . A perpendicular magnetic recording medium produced by the method according to  claim 7 .  
     
     
         17 . A perpendicular magnetic recording medium produced by the method according to  claim 8 .  
     
     
         18 . A perpendicular magnetic recording medium produced by the method according to  claim 9.