Magnetic powder suitable for low-noise media

Abstract

An iron system magnetic powder, and particularly an iron system magnetic powder comprised chiefly of Fe 16 N 2 , is provided that has an atomic ratio of total noble metal content to Fe of 0.01-10%. The magnetic powder can be produced by subjecting iron oxy-hydroxide or iron oxide having an atomic ratio of total noble metal content to Fe of 0.01-10% to reduction treatment. The average particle volume of the magnetic powder is preferably 4,000 nm 3 or less. The magnetic powder is suitable for fabricating high recording density media of low noise, high output and high C/N ratio that are suitable for use with a GMR head or the like.

1 . An iron system magnetic powder having an atomic ratio of total noble metal content to Fe of 0.01-10%.  
     
     
         2 . A magnetic powder comprised chiefly of Fe 16 N 2  having an atomic ratio of total noble metal content to Fe of 0.01-10%.  
     
     
         3 . A magnetic powder according to  claim 1  produced by subjecting iron oxy-hydroxide or iron oxide having an atomic ratio of total noble metal content to Fe of 0.01-10% to reduction treatment.  
     
     
         4 . A magnetic powder according to  claim 2  produced by subjecting iron oxy-hydroxide or iron oxide having an atomic ratio of total noble metal content to Fe of 0.01-10% to reduction treatment and then to nitriding treatment.  
     
     
         5 . A magnetic powder according to  claim 1 , whose average particle volume is 4,000 nm 3  or less.  
     
     
         6 . A magnetic recording medium that uses a magnetic powder of  claim 1  in a magnetic layer.  
     
     
         7 . A magnetic powder according to  claim 2  produced by subjecting iron oxy-hydroxide or iron oxide having an atomic ratio of total noble metal content to Fe of 0.01-10% to reduction treatment.  
     
     
         8 . A magnetic powder according to  claim 2 , whose average particle volume is 4,000 nm 3  or less.  
     
     
         9 . A magnetic powder according to  claim 3 , whose average particle volume is 4,000 nm 3  or less.  
     
     
         10 . A magnetic powder according to  claim 4 , whose average particle volume is 4,000 nm 3  or less.  
     
     
         11 . A magnetic recording medium that uses a magnetic powder of  claim 2  in a magnetic layer.  
     
     
         12 . A magnetic recording medium that uses a magnetic powder of  claim 3  in a magnetic layer.  
     
     
         13 . A magnetic recording medium that uses a magnetic powder of  claim 4  in a magnetic layer.  
     
     
         14 . A magnetic recording medium that uses a magnetic powder of  claim 5  in a magnetic layer.