Magnetic material, method for producing the same, and magnetic recording medium

Abstract

A magnetic material having a structure of a material having a ferromagnetic phase at ordinary temperature as a core and a material having an antiferromagnetic phase at ordinary temperature surrounding the periphery of the core in the form of a shell, wherein a ratio between a volume of the ferromagnetic phase material and the volume of the antiferromagnetic phase material in the magnetic material is in a range where no exchange biasing field of the magnetic material appears and a rotational hysteresis loss of the magnetic material is made the maximum, a method of producing the same, and a magnetic recording medium using the same.

1 - 12 . (canceled)  
     
     
         13 . A magnetic material formed as an aggregate of a plurality of antiferromagnetic phases and a plurality of ferromagnetic phases wherein the phases are maintained at a temperature of 300° K or higher and 
 wherein a ratio between a volume of said ferromagnetic phase material and a volume of said antiferromagnetic phase material is in a range where substantially no exchange biasing field appears and a rotational hysteresis loss becomes maximum or less than but substantially close to said maximum.    
     
     
         14 . A magnetic material as set forth in  claim 13 , wherein said ferromagnetic phase material comprises at least Fe, Co, or an alloy having Fe or Co as an ingredient.  
     
     
         15 . A magnetic material as set forth in  claim 13 , wherein said ferromagnetic phase material comprises an alloy including at least Pt, Cr, or an Fe oxide-based magnetic material.  
     
     
         16 . A magnetic material as set forth in  claim 13 , wherein said antiferromagnetic phase material includes at least an oxide of one of Ni, Co, Fe, and Cr, or a fluoride of an alloy of one of Fe, Mn, and Ni with K.  
     
     
         17 . A magnetic material as set forth in  claim 13 , wherein said antiferromagnetic phase material comprises an alloy including at least Mn or Cr.  
     
     
         18 - 30 . (canceled)  
     
     
         31 . A magnetic material formed as an aggregate of a plurality of antiferromagnetic phases and a plurality of ferromagnetic phases wherein the phases are maintained at a temperature of 300° K or higher; and 
 wherein a ratio between a volume of said ferromagnetic phase material and a volume of said antiferromagnetic phase material is in a range where substantially no exchange biasing field appears and a rotational hysteresis loss becomes a maximum or less than but substantially close to said maximum;    wherein said ferromagnetic phase material comprises at least Fe, Co, or an alloy having Fe or Co as an ingredient,    wherein said ferromagnetic phase material comprises at least Fe, Co, or an alloy having Fe or Co as an ingredient; and