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 - 8 . (Canceled)  
     
     
         9 . A method for producing a magnetic material having a core formed by a material having a ferromagnetic phase at ordinary temperature and having a shell formed by coating a periphery of said core by a material having an antiferromagnetic phase at ordinary temperature, said method comprising the steps of: 
 forming said ferromagnetic core from a predetermined ferromagnetic material, surrounding said ferromagnetic core by a predetermined material for forming said antiferromagnetic shell, and    causing a reaction in an outer periphery of the predetermined material for forming said antiferromagnetic shell in a predetermined atmosphere to form said antiferromagnetic shell.    
     
     
         10 . A method for producing a magnetic material as set forth in  claim 9 , further comprising, in the step of forming said ferromagnetic core, heating said predetermined ferromagnetic material for forming said ferromagnetic core and cooling said heated ferromagnetic material to increase a component of a hexagonal closest-packed structure in the crystal structure of said ferromagnetic material.  
     
     
         11 . A method for producing a magnetic material as set forth in  claim 9 , further comprising forming said ferromagnetic core to a predetermined size and forming said antiferromagnetic shell to a predetermined thickness based on a ratio between a volume of said ferromagnetic phase material and a volume of said antiferromagnetic phase material, which is in a range where no exchange biasing field appears in said magnetic material and a rotational hysteresis loss becomes maximum.  
     
     
         12 - 19  (Canceled) Please cancel claims  12 - 19 .