Perpendicular magnetic recording media

Abstract

A perpendicular magnetic recording medium having a good thermal stability and a high recording density is provided. The perpendicular magnetic recording medium includes at least a first and a second perpendicular magnetic recording layer and a substrate supporting the first and the second perpendicular magnetic recording layers. The first and the second perpendicular magnetic recording layers have different physical/magnetic properties and are formed of materials that compensate the different physical/magnetic properties. The first and the second perpendicular magnetic recording layers are selected from a layer for improving perpendicular magnetic anisotropic energy (Ku), a layer for reducing the size of crystal grains, a layer for reducing the size of magnetic domains, a layer for increasing an SNR, a layer for improving signal output, a layer for reducing noise, a layer for improving the uniformity of crystal grain sizes, and a layer for improving the uniformity of magnetic domain sizes.

1 - 2 . (canceled)  
     
     
         3 . The perpendicular magnetic recording medium of claim  1 , wherein the first perpendicular magnetic recording layer has smaller crystal grains than the crystal grains of the second perpendicular magnetic recording layer, and the second perpendicular magnetic recording layer has higher perpendicular magnetic anisotropic energy (Ku) than the first perpendicular magnetic recording layer.  
     
     
         4 . The perpendicular magnetic recording medium of claim  1 , wherein the first perpendicular magnetic recording layer has higher perpendicular magnetic anisotropic energy (Ku) than the second perpendicular magnetic recording layer, and the second perpendicular magnetic recording layer is used to reduce noise.  
     
     
         5 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layer is used to improve perpendicular magnetic anisotropic energy (Ku), and the other perpendicular magnetic recording layer is used to reduce the size of crystal grains.  
     
     
         6 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layers is used to improve perpendicular magnetic anisotropic energy (Ku), and the other perpendicular magnetic recording layer is used to reduce the size of magnetic domains.  
     
     
         7 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layers is used to improve perpendicular magnetic anisotropic energy (Ku), and the other perpendicular magnetic recording layer is used to increase the uniformity of crystal grain sizes.  
     
     
         8 - 10 . (canceled)  
     
     
         11 . The perpendicular magnetic recording medium of claim  1 , wherein the perpendicular magnetic recording layers have amorphous structures.  
     
     
         12 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layers has a crystalline structure, and the other perpendicular magnetic recording layer has an amorphous structure.  
     
     
         13 . (canceled)  
     
     
         14 . The perpendicular magnetic recording medium of claim  1 , wherein the perpendicular magnetic recording layers have magnetic domains that are physically connected to one another.  
     
     
         15 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layers has magnetic domains that are physically disconnected from one another, and the other perpendicular magnetic recording layer has magnetic domains that are physically connected to one another.  
     
     
         16 . The perpendicular magnetic recording medium of claim  1 , wherein both the first and second perpendicular magnetic recording layers have a weak exchange coupling between magnetic particles.  
     
     
         17 - 31 . (canceled)  
     
     
         32 . The perpendicular magnetic recording medium of claim  1 , wherein one of the first and second perpendicular magnetic recording layers has a lattice matching structure, and the other perpendicular magnetic recording layer has a lattice mismatching structure.