Patent ID: 8338006

Claim:
A magnetic recording disk comprising: a substrate having a plurality of elevated lands and recessed grooves; a magnetic recording layer on the elevated lands; a carbon-containing protective overcoat on the magnetic recording layer and recessed grooves, the recessed grooves having a gap width W, the gap depth D from the top of the overcoat on the lands to the top of the overcoat on the recessed grooves being equal to or greater than 30 nm; and a coating on the overcoat on the lands and in the recessed grooves and comprising: a cross-linked functionalized-perfluorinated polyether (PFPE) layer having functional end groups bonded to the carbon-containing overcoat and a recession R1 between the top of said functionalized-PFPE layer on the lands and the top of said functionalized-PFPE layer in the recessed grooves, where a negative value of R1 is measured in the direction from the top of said functionalized-PFPE layer on the lands toward the substrate; and a cross-linked non-functionalized-PFPE layer on the functionalized-PFPE layer, wherein the recession between the top of said non-functionalized-PFPE layer on the lands and the top of said non-functionalized-PFPE layer in the recessed grooves is R2, where a negative value of R2 is measured in the direction from the top of said non-functionalized-PFPE layer on the lands toward the substrate; wherein for a D of 30 nm or greater than 30 nm, the recession improvement (R1-R2)is equal to minus 5 nm or more negative than minus 5 nm for a W between about 70 nm and 100 nm.