Perpendicular magnetic recording disk with patterned template layer
View Patent ↗A perpendicular magnetic recording (PMR) disk has a patterned template layer for the growth of the magnetic grains and the nonmagnetic material surrounding the grains. The template layer is a substantially planar platinum (Pt) or palladium (Pd) layer that is patterned to have Pt or Pd regions arranged in a hexagonal-close-packed (hcp) pattern with the Pt or Pd regions surrounded by Pt-oxide or Pd-oxide regions. The two separate regions of the template layer have different surface chemistries and energies, which provide a “chemical contrast” to impinging atoms during deposition of the metallic magnetic material and nonmagnetic (typically oxide) material, effectively guiding the deposition. The metallic magnetic material is preferentially deposited on the pristine, epitaxial Pt or Pd regions to form the magnetic grains, while the oxide migrates to the oxidized Pt or Pd regions due to the matching of lower surface energy.
1. A perpendicular magnetic recording disk comprising:
a substrate;
a substantially planar template layer on the substrate comprising patterned regions selected from the group consisting of Pt and Pd arranged in a substantially hexagonal-close packed (hcp) pattern and surrounded by oxide regions of said selected Pt or Pd; and
a perpendicular magnetic recording layer on the template layer and comprising a ferromagnetic alloy and one or more oxides selected from the group consisting of oxides of Si, Ta, Ti and Nb; wherein said ferromagnetic alloy is formed substantially on said selected Pt or Pd patterned regions and said recording layer oxides are formed substantially on said template layer oxide regions.
2. The disk of claim 1 wherein the ferromagnetic alloy is an alloy comprising Co, Pt and Cr.
3. The disk of claim 1 wherein the ferromagnetic alloy is a FePt alloy with a composition of the form Fe (y) Pt (100-y) , where y is between about 45 and 55 atomic percent.
4. The disk of claim 1 wherein the ferromagnetic alloy is a CoPt alloy of the form Co (x) Pt (100-x) , where x is between about 45 and 55 atomic percent.
5. The disk of claim 1 further comprising an underlayer on the substrate and selected from the group consisting of an alloy of Ni and Ta, an alloy of Ni and W and an alloy of Ni, W and Cr; wherein the template layer is on and in contact with said underlayer.
6. The disk of claim 5 wherein the underlayer comprises a bilayer of a NiTa alloy layer and a NiW alloy layer on the NiTa alloy layer; and wherein the template layer is on and in contact with the NiW alloy layer.
7. The disk of claim 1 wherein said selected Pt or Pd patterned regions are Pt patterned regions.
8. A perpendicular magnetic recording disk comprising:
a substrate;
an underlayer on the substrate;
a substantially planar template layer on the underlayer, the template layer having metal regions selected from the group consisting of Pt and Pd arranged in a substantially hexagonal-close packed (hcp) pattern and surrounded by oxide regions of said selected Pt or Pd; and
a perpendicular magnetic recording layer on the template layer and comprising Co alloy ferromagnetic grains formed on said selected Pt or Pd regions and one or more oxides selected from the group consisting of oxides of Si, Ta, Ti and Nb formed on said template layer oxide regions.
9. The disk of claim 8 wherein the underlayer is selected from the group consisting of an alloy of Ni and Ta, an alloy of Ni and W and an alloy of Ni, W and Cr.
10. The disk of claim 9 wherein the underlayer comprises a bilayer of a NiTa alloy layer and a NiW alloy layer on the NiTa alloy layer.
11. The disk of claim 8 wherein said selected metal regions are Pt regions.
12. The disk of claim 8 wherein said Co alloy ferromagnetic grains comprise CoPtCr alloy grains.
13. The disk of claim 8 further comprising a protective overcoat on the recording layer.