Magnetic recording medium and magnetic recording apparatus

Abstract

It is an object of the present invention to provide a high reliability magnetic storage apparatus capable of performing writing and reading back of high density information. The magnetic storage apparatus is so configured as to have a longitudinal magnetic recording medium including: a magnetic layer formed on a non-magnetic substrate via a plurality of underlayers; the magnetic layer including a lower magnetic layer containing Ru in an amount of not less than 3 at % to not more than 30 at %, and Cr in an amount of not less than 0 at % to not more than 18 at %, and further containing at least one of B or C in an amount of not less than 0 at % to not more than 20 at %, and an upper magnetic layer containing Co as a main component disposed thereon via a non-magnetic intermediate layer.

1 - 16 . (canceled)  
     
     
         17 . A magnetic recording medium comprising: 
 a non-magnetic substrate;    a magnetic layer including a first magnetic film, a second magnetic film, and a non-magnetic film; and    a plurality of underlayers provided between said non-magnetic substrate and said magnetic layer,    wherein said first magnetic film is provided between said plurality of underlayers and said non-magnetic film and comprises Co,    wherein said first and second films are anti-ferromagnetically coupled via said non-magnetic film, and    wherein said plurality of underlayers comprises a first film of a body-centered cubic structure, which includes Cr, Mo, and 2 at % to 10 at % of B.    
     
     
         18 . The magnetic recording medium according to  claim 17 , 
 wherein, in said first film, Cr is a main component.    
     
     
         19 . The magnetic recording medium according to  claim 18 , 
 wherein said plurality of underlayers further comprises a second film which is non-magnetic and has an amorphous structure.    
     
     
         20 . The magnetic recording medium according to  claim 18 , 
 wherein said first film is provided between said second film and said non-magnetic substrate.    
     
     
         21 . The magnetic recording medium according to  claim 19 , 
 wherein said plurality of the underlayers further comprises a third film comprising a non-magnetic and hexagonal close-packed structured alloy material containing Co.    
     
     
         22 . The magnetic recording medium according to  claim 21 , 
 wherein said third film is provided between said first magnetic film and said second film.    
     
     
         23 . The magnetic recording medium according to  claim 21 , 
 wherein said third film further includes 35 at % to 60 at % of Ru.    
     
     
         24 . A magnetic recording medium comprising: 
 a non-magnetic substrate;    a magnetic layer including a first magnetic film, a second magnetic film, and a non-magnetic film; and    a plurality of underlayers provided between said non-magnetic substrate and said magnetic layer,    wherein said first magnetic film is provided between said plurality of underlayers and said non-magnetic film and comprises Co and Cu,    wherein said first and second films are anti-ferromagnetically coupled via said non-magnetic film, and    wherein said plurality of underlayers comprises a first film of a body-centered cubic structure, which includes Cr, Mo, and 2 at % to 10 at % of B.    
     
     
         25 . The magnetic recording medium according to  claim 24 , 
 wherein, in said first film, Cr is a main component, and    wherein, in said first magnetic film, Co is a main component.    
     
     
         26 . The magnetic recording medium according to  claim 24 , 
 wherein said plurality of underlayers further comprises a second film which is non-magnetic and has an amorphous structure.    
     
     
         27 . The magnetic recording medium according to  claim 26 , 
 wherein said first film is provided between said second film and said non-magnetic substrate.    
     
     
         28 . The magnetic recording medium according to  claim 24 , 
 wherein said plurality of underlayers further comprises a third film comprising a non-magnetic and hexagonal close-packed structured alloy material containing Co.    
     
     
         29 . The magnetic recording medium according to  claim 28 , 
 wherein said third film is provided between said first magnetic film and said second film.    
     
     
         30 . The magnetic recording medium according to  claim 28 , 
 wherein said third film further includes 35 at % to 60 at % of Ru.    
     
     
         31 . A magnetic recording medium comprising: 
 a non-magnetic substrate;    a magnetic layer including a first magnetic film, a second magnetic film, and a non-magnetic film; and    a plurality of underlayers provided between said non-magnetic substrate and said magnetic layer,    wherein said first magnetic film is provided between said plurality of underlayers and said non-magnetic film and comprises 3 at % to 30 at % of Ru or Re, less than or equal to 18 at % of Cr, and less than or equal to 20 at % of B or C, and Co,    wherein said first and second films are anti-ferromagnetically coupled via said non-magnetic film, and    wherein said plurality of underlayers comprises a first film of a body-centered cubic structure, which includes Cr, Mo, and 2 at % to 10 at % of B.    
     
     
         32 . The magnetic recording medium according to  claim 31 , 
 wherein said plurality of underlayers further comprises a second film which is non-magnetic and has an amorphous structure.    
     
     
         33 . The magnetic recording medium according to  claim 31 , 
 wherein said first film is provided between said second film and said non-magnetic substrate.    
     
     
         34 . The magnetic recording medium according to  claim 32 , 
 wherein said plurality of underlayers further comprises a third film comprising a non-magnetic and hexagonal close-packed structured alloy material containing Co.    
     
     
         35 . The magnetic recording medium according to  claim 34 , 
 wherein said third film is provided between said first magnetic film and said second film.    
     
     
         36 . The magnetic recording medium according to  claim 35 , 
 wherein said third film further includes 35 at % to 60 at % of Ru.