Perpendicular recording magnetic media having a granular magnetic recording layer and an amorphous soft underlayer

Abstract

A perpendicular magnetic recording medium having a substrate, an amorphous soft underlayer of thickness 30 nm or greater, and a granular magnetic recording layer for perpendicular recording is disclosed. The granular magnetic recording layer includes a non-magnetic region between magnetic grains, wherein the non-magnetic region includes metal nitride or metal carbide and provides exchange decoupling between the magnetic grains. The perpendicular recording medium of this invention reduces DC noise and increases media signal-to-noise ratio; it reduces surface roughness, which in turn reduces the head-to-media spacing and the head-to-amorphous soft underlayer spacing.

1 . A method comprising forming a magnetic recording layer on a substrate via reactive sputtering in an atmosphere containing at least one of NH 3  or hydrocarbon gas, wherein the formed magnetic recording layer includes non-magnetic regions between magnetic grains, the non-magnetic regions comprising at least one of a metal nitride or metal carbide. 
     
     
         2 . The method of  claim 1 , wherein the metal nitride comprises at least one of cobalt nitride, boron nitride, aluminum nitride, titanium nitride, silicon nitride, zirconium nitride, vanadium nitride, tantalum nitride, chromium nitride, or molybdenum nitride. 
     
     
         3 . The method of  claim 1 , wherein the metal carbide comprises at least one of cobalt carbide, boron carbide, aluminum carbide, titanium carbide, silicon carbide, zirconium carbide, vanadium carbide, tantalum carbide, chromium carbide, or molybdenum carbide. 
     
     
         4 . The method of  claim 1 , wherein the magnetic grains comprise CoPtX, wherein X is selected from the group consisting of Al, Ti, V, Cr, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, and Au, and combinations thereof. 
     
     
         5 . The method of  claim 1 , further comprising:
 forming soft underlayer on the substrate, wherein the soft underlayer is between the substrate and magnetic recording layer.   
     
     
         6 . The method of  claim 5 , wherein the soft underlayer comprises at least one or Co or Fe. 
     
     
         7 . The method of  claim 6 , wherein the soft underlayer comprises one or more of Zr, Nb, Ta, or B. 
     
     
         8 . The method of  claim 5 , wherein the soft magnetic underlayer is thicker than the magnetic recording layer. 
     
     
         9 . The method of  claim 5 , wherein the soft underlayer has an average surface roughness of less than approximately 0.3 nm. 
     
     
         10 . The method of  claim 15 , wherein the magnetic recording layer has a thickness of less than approximately 12 nm. 
     
     
         11 . A magnetic recording layer medium comprising:
 a substrate;   a soft underlayer; and   a magnetic recording layer comprising non-magnetic regions between magnetic grains, wherein the non-magnetic regions comprise at least one of metal nitride or metal carbide, wherein the soft underlayer has a surface roughness of less than 0.3 nm and comprises at least one of Fe or Co, and wherein the soft underlayer is between the substrate and magnetic recording layer.   
     
     
         12 . The magnetic recording medium of  claim 11 , wherein the soft underlayer further comprises at least one of a Zr or B. 
     
     
         13 . The magnetic recording medium of  claim 11 , wherein the soft underlayer comprises one or more of a CoFeZr-alloy, FeCoZrB-alloy, or FeCoB-alloy. 
     
     
         14 . The magnetic recording medium of  claim 11 , wherein the metal nitride comprises at least one of cobalt nitride, boron nitride, aluminum nitride, titanium nitride, silicon nitride, zirconium nitride, vanadium nitride, tantalum nitride, chromium nitride, or molybdenum nitride. 
     
     
         15 . The magnetic recording medium of  claim 11 , wherein the metal carbide comprises at least one of cobalt carbide, boron carbide, aluminum carbide, titanium carbide, silicon carbide, zirconium carbide, vanadium carbide, tantalum carbide, chromium carbide, or molybdenum carbide. 
     
     
         16 . The method of  claim 11 , wherein the magnetic grains comprise CoPtX, wherein X is selected from the group consisting of Al, Ti, V, Cr, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, and Au, and combinations thereof.