Magnetic recording medium, a method of manufacturing the same, and a magnetic storage using the magnetic recording medium

Abstract

A magnetic recording medium and method of manufacturing thereof facilitates to prevent a film inflation from occurring in an environmental condition range between −40° C. and 80° C. and an 80% relative humidity. The magnetic recording medium includes a plastic substrate and an undercoating layer on the plastic substrate. The undercoating layer is provided with a columnar structure, which prevents water (moisture) between the plastic substrate and the undercoating layer from aggregating and, therefore, the film inflation from occurring.

What is claimed is:  
     
         1 . A magnetic recording medium, comprising: 
 a nonmagnetic substrate made of a polymer resin;    a magnetic layer above the nonmagnetic substrate;    a protection layer above the magnetic layer; and    a liquid lubricant layer on the protection layer.    
     
     
         2 . The magnetic recording medium according to  claim 1 , further comprising: 
 a nonmagnetic undercoating layer on the nonmagnetic substrate.    
     
     
         3 . The magnetic recording medium according to  claim 2 , wherein the nonmagnetic undercoating layer comprises Ru, Re, Os, or Mo.  
     
     
         4 . The magnetic recording medium according to  claim 3 , wherein the nonmagnetic undercoating layer comprises an alloy comprising Ru, Re, Os, or Mo.  
     
     
         5 . The magnetic recording medium according to  claim 2 , wherein the nonmagnetic undercoating layer comprises an alloy comprising W and Ti, Zr, or Cr.  
     
     
         6 . The magnetic recording medium according to  claim 2 , wherein the nonmagnetic undercoating layer comprises an alloy comprising Ni and P.  
     
     
         7 . The magnetic recording medium according to  claim 2 , further comprising: 
 an intermediate layer on the nonmagnetic undercoating layer.    
     
     
         8 . The magnetic recording medium according to  claim 7 , wherein the intermediate layer comprises Ru, Re, Os, or Mo as a main component thereof.  
     
     
         9 . The magnetic recording medium according to  claim 8 , wherein the intermediate layer comprises an alloy comprising Ru, Re, Os, or Mo.  
     
     
         10 . The magnetic recording medium according to  claim 7 , wherein the intermediate layer comprises an alloy comprising W and Ti, Zr, or Cr.  
     
     
         11 . The magnetic recording medium according to  claim 7 , wherein the intermediate layer comprises an alloy comprising Ni and P.  
     
     
         12 . A method of manufacturing a magnetic recording medium comprising a nonmagnetic substrate made of a polymer resin, a magnetic layer above the nonmagnetic substrate, a protection layer above the magnetic layer, and a liquid lubricant layer on the protection layer, the method comprising: 
 forming an undercoating layer on the nonmagnetic substrate under a pressure of 5 mTorr or higher.    
     
     
         13 . The method of manufacturing the magnetic recording medium described in  claim 12 , the method comprising: 
 forming the undercoating layer under a pressure of 60 mTorr or higher.    
     
     
         14 . The method according to  claim 12 , wherein the undercoating layer comprises a CrW alloy.  
     
     
         15 . The method according to  claim 12 , wherein the undercoating layer comprises an Mo as a main component thereof.  
     
     
         16 . The method according to  claim 12 , wherein the undercoating layer comprises an NiP alloy.  
     
     
         17 . The method according to  claim 13 , wherein the undercoating layer comprises a TiW alloy.  
     
     
         18 . The method according to  claim 13 , wherein the undercoating layer comprises Ru, Re or Os as a main component thereof.  
     
     
         19 . A method of manufacturing a magnetic recording medium comprising a nonmagnetic substrate made of a polymer resin, a magnetic layer above the nonmagnetic substrate, a protection layer above the magnetic layer, and a liquid lubricant layer on the protection layer, the method comprising: 
 forming an intermediate layer on the nonmagnetic substrate under a pressure of 5 mTorr or higher.    
     
     
         20 . The method of manufacturing the magnetic recording medium described in  claim 19 , the method comprising: 
 forming the intermediate layer under a pressure of 60 mTorr or higher.    
     
     
         21 . The method according to  claim 19 , wherein the intermediate layer comprises a CrW alloy.  
     
     
         22 . The method according to  claim 19 , wherein the intermediate layer comprises Mo as a main component thereof.  
     
     
         23 . The method according to  claim 19 , wherein the intermediate layer comprises an NiP alloy.  
     
     
         24 . The method according to  claim 20 , wherein the intermediate undercoating layer comprises a TiW alloy.  
     
     
         25 . The method according to  claim 20 , wherein the intermediate layer comprises Ru, Re or Os as a main component thereof.  
     
     
         26 . A magnetic storage, comprising: 
 a magnetic recording medium mounted thereon, the magnetic recording medium comprising a nonmagnetic substrate made of a polymer resin, a magnetic layer above the nonmagnetic substrate, a protection layer above the magnetic layer, and a liquid lubricant layer on the protection layer.    
     
     
         27 . The magnetic storage according to  claim 26 , further comprising a nonmagnetic undercoating layer on the nonmagnetic substrate.  
     
     
         28 . The magnetic recording medium according to  claim 26 , further comprising: 
 an intermediate layer on the nonmagnetic undercoating layer.