Magnetic recording medium, magnetic recording apparatus and magnetic recording method

Abstract

A magnetic recording medium capable of alleviating thermal fluctuation and improving the recording density includes a functional layer containing a magnetic material, and a recording layer overlying the functional layer and containing a magnetic material. The recording layer contains a plurality of magnetic grains and a nonmagnetic material existing among the magnetic grains, and the functional layer and the recording layer exert exchange coupling interaction in a direction making a substantially orthogonal relation with each other at room temperature.

1 . A magnetic recording medium comprising: 
 a functional layer containing a first magnetic material; and    a recording layer stacked on said functional layer and containing a second magnetic material,    said first magnetic material and said second magnetic material exerting exchange coupling interaction in a direction making a substantially orthogonal relation with each other at room temperature.    
     
     
         2 . A magnetic recording medium according to  claim 1 , wherein said second magnetic material includes a plurality of magnetic grains and a nonmagnetic material existing among said magnetic grains.  
     
     
         3 . A magnetic recording medium according to  claim 1 , wherein each of said first and second magnetic materials has magnetic anisotropy in a direction substantially in parallel to a film surface.  
     
     
         4 . A magnetic recording medium according to  claim 3 , wherein said magnetic recording medium is in form of a disk, and one of said first and second magnetic materials has magnetic anisotropy in a direction substantially in parallel to a radial direction of said disk whereas the other of said first and second magnetic materials has magnetic anisotropy in a direction substantially orthogonal to a radial direction of said disk.  
     
     
         5 . A magnetic recording medium according to  claim 1 , wherein one of said first and second magnetic materials has magnetic anisotropy in a direction substantially in parallel to a film surface, and the other of said first and second magnetic materials has magnetic anisotropy in a direction substantially perpendicular to the film surface.  
     
     
         6 . A magnetic recording medium according to  claim 1 , wherein said first magnetic material is made of a continuous magnetic material.  
     
     
         7 . A magnetic recording medium according to  claim 1 , wherein said first magnetic material includes a plurality of magnetic grains and a nonmagnetic material existing among said magnetic grains.  
     
     
         8 . A magnetic recording medium according to  claim 7 , wherein said magnetic grains contained in said first magnetic material have an average size larger than an average size of said magnetic grains contained in said second magnetic material.  
     
     
         9 . A magnetic recording medium according to  claim 1 , further comprising a spacer layer provided between said functional layer and said recording layer and different in composition from said functional layer and said recording layer.  
     
     
         10 . A magnetic recording medium according to  claim 9 , wherein said spacer layer is made of an alloy containing at least one of manganese (Mn) and chromium (Cr).  
     
     
         11 . A magnetic recording medium according to  claim 9 , wherein said spacer layer is made of a nonmagnetic material added with at least one element selected from cobalt (Co) iron (Fe), nickel (Ni), manganese (Mn), chromium (Cr), platinum (Pt) and palladium (Pd).  
     
     
         12 . A magnetic recording medium according to  claim 1 , wherein a hysteresis loop of the recording medium shows an inflection corresponding to a decrease in magnetization where a spin of the functional layer and a spin of the recording layer are substantially orthogonal to each other.  
     
     
         13 . A magnetic recording medium according to  claim 1 , wherein the functional layer and the recording layer are consecutively formed without breaking a vacuum.