Patterned-media perpendicular magnetic recording disk with servo regions having magnetized servo pillars and oppositely-magnetized servo trenches

A patterned-media perpendicular magnetic recording disk comprising:

• a substrate having a generally planar surface;
• a plurality of spaced-apart data pillars extending generally perpendicularly from said substrate surface and arranged in generally concentric circular tracks for generating data signals, the data pillars defining data trenches at said substrate surface between the data pillars;
• a plurality of angularly-spaced nondata servo sectors for generating servo signals, each servo sector comprising a plurality of spaced-apart nondata servo pillars extending generally perpendicularly from said substrate surface, the servo pillars defining servo trenches at said substrate surface between the servo pillars;
• magnetizable material on the data pillars and servo pillars and in the servo trenches and having perpendicular magnetic anisotropy, the magnetizable material selected from the group consisting of (a) a Co/Ni multilayer, (b) a multilayer of alternating films of a first film selected from Co, Fe, CoFe, CoNi and FeNi, and a second film selected from Pt and Pd, (c) a binary alloy selected from CoPt, CoPd, FePt, FePd, CoPt3, CO3Pt, CoPd3 and CO3Pd, and (d) an alloy selected from (Co(y)Pt(100-y))—X and (Fe(y)Pt(100-y))—X, where y is between about 45 and 55 atomic percent and the element X is selected from the group consisting of Ni, Au, Cu, Pd and Ag and is present in an amount greater than zero atomic percent and less than or equal to 20 atomic percent;
• and wherein
• the servo pillars have a magnetization in the same perpendicular direction and the servo trenches have a magnetization in the opposite perpendicular direction, whereby the peak-to-peak amplitude between the magnetization of a servo pillar and the magnetization of an oppositely-magnetized adjacent servo trench represents a servo signal;
• the data trenches have substantially no magnetization and the data pillars have a magnetization opposite the magnetization direction of the servo trenches;
• the servo pillars have a height (h) above the substrate surface and are spaced apart on the substrate surface by a distance (t1) representing the characteristic dimension of the servo trenches, wherein t1 is equal to or greater than 2 h;
• and
• the data pillars have a height (h) above the substrate surface and are spaced apart on the substrate surface by a distance (t2) representing the characteristic dimension of the data trenches, wherein h is greater than or equal to t2.

A method for making a patterned-media perpendicular magnetic recording disk comprising:

• providing a substrate having a generally planar surface and a plurality of data pillars and a plurality of nondata servo pillars extending generally perpendicularly from said substrate surface, the data pillars arranged in generally concentric circular tracks and spaced-apart to define data trenches at said substrate surface between the data pillars, the height of the data pillars above the substrate surface being greater than or equal to the spacing between the data pillars on the substrate surface, and the nondata servo pillars arranged in angularly-spaced nondata servo sectors extending generally radially across the tracks and spaced apart to define servo trenches at said substrate surface between the servo pillars;
• sputter depositing on the substrate surface a multilayer of alternating layers of a first material and a second material, said first material/second material multilayer selected from the group consisting of Co/Ni, Co/Pt, Co/Pd, Fe/Pt, Fe/Pd, CoFe/Pt, CoFe/Pd, CoNi/Pt, CoNi/Pd, FeNi/Pt and FeNi/Pd, said multilayer having perpendicular magnetic anisotropy;
• applying a first magnetic field in a first direction perpendicular to the substrate surface to magnetize said multilayer on the data pillars and servo pillars and in the servo trenches in the same perpendicular direction;
• and
• applying a second magnetic field less than the first magnetic field in a second direction perpendicular to the substrate surface and opposite said first direction to reverse the magnetization of said multilayer in the servo trenches without reversing the magnetization of said multilayer on the data pillars and servo pillars.