Granted Patent B2

US 8,603,650 · App. 10/576,755 · Granted Dec 10, 2013

Abstract

Claims (15)

1. A perpendicular magnetic recording disk for use in perpendicular magnetic recording, said perpendicular magnetic recording disk characterized by comprising a substrate, a soft magnetic layer of a material selected from a group consisting of an Fe-based material and a Co-based material on said substrate, and a magnetic recording layer on said soft magnetic layer, wherein said magnetic recording layer comprises a ferromagnetic layer on said soft magnetic layer, having a granular structure, and comprising crystal grains mainly made of cobalt (Co) and grain boundary portions mainly made of SiO 2 , a spacer layer selected from a group consisting of a Pd layer and a Pt layer on said ferromagnetic layer, and a layer, on said spacer layer, having no granular structure and comprising alternating films of Co or an alloy thereof and Pd or alternating films of Co or an alloy thereof and Pt, the content of the SiO 2 in said ferromagnetic layer being 8 at% to 15 at%, said perpendicular magnetic recording disk comprising, on said substrate, said soft magnetic layer, said ferromagnetic layer having the granular structure, said spacer layer, and said layer having no granular structure in this order; wherein the layer having no granular structure comprises at least two films of Co or an alloy thereof and at least two films of Pd or Pt.

2. A perpendicular magnetic recording disk according to claim 1 , further comprising an underlayer including Ru provided between said soft magnetic layer and said ferromagnetic layer.

3. The perpendicular magnetic recording disk according to claim 1 , wherein the content of the SiO 2 in said ferromagnetic layer is 10 at% to 15 at%.

4. The perpendicular magnetic recording disk according to claim 1 , wherein the content of the SiO 2 in said ferromagnetic layer is 12 at%.

5. The perpendicular magnetic recording disk according to claim 4 , wherein the layer having no granular structure comprises five films of Co or an alloy thereof and five films of Pd or Pt.

6. A method of manufacturing a perpendicular magnetic recording disk for use in perpendicular magnetic recording and having at least a soft magnetic layer of a material selected from a group consisting of an Fe-based material and a Co-based material on a substrate and a magnetic recording layer on said soft magnetic layer, said method characterized by, in a step of forming said magnetic recording layer comprising, on said soft magnetic layer, a ferromagnetic layer of a granular structure comprising SiO 2 between crystal grains comprising cobalt (Co), the content of the SiO 2 in said ferromagnetic layer being 8 at% to 15 at%, a spacer layer selected from a group consisting of a Pd layer and a Pt layer on said ferromagnetic layer, and a layer, on said spacer layer, having no granular structure and comprising alternating films of Co or an alloy thereof and Pd or alternating films of Co or an alloy thereof and Pt, forming said ferromagnetic layer on said soft magnetic layer by sputtering in an argon gas atmosphere and then forming said layer having no granular structure by sputtering in an argon gas atmosphere at a gas pressure lower than a gas pressure used when forming said ferromagnetic layer,

said method thereby manufacturing said perpendicular magnetic recording disk comprising, on said substrate, said soft magnetic layer, said ferromagnetic layer having the granular structure, said spacer layer, and said layer having no granular structure in this order,

wherein the layer having no granular structure comprises at least two films of Co or an alloy thereof and at least two films of Pd or Pt.

7. The method of manufacturing a perpendicular magnetic recording disk according to claim 6 , wherein the content of the SiO 2 in said ferromagnetic layer is 10 at% to 15 at%.

8. The method of manufacturing a perpendicular magnetic recording disk according to claim 6 , wherein the content of the SiO 2 in said ferromagnetic layer is 12 at%.

9. The method of manufacturing a perpendicular magnetic recording disk according to claim 8 , wherein the layer having no granular structure comprises five films of Co or an alloy thereof and five films of Pd or Pt.

10. A method of manufacturing a perpendicular magnetic recording disk for use in perpendicular magnetic recording and having at least a soft magnetic layer of a material selected from a group consisting of an Fe-based material and a Co-based material on a substrate, an underlayer including Ru on said soft magnetic layer, and a magnetic recording layer on said underlayer, said method characterized by,

in a step of forming said magnetic recording layer comprising, on said underlayer, a ferromagnetic layer of a granular structure comprising SiO 2 between crystal grains comprising cobalt (Co), the content of the SiO 2 in said ferromagnetic layer being 8 at% to 15 at%, a spacer layer selected from a group consisting of a Pd layer and a Pt layer on said ferromagnetic layer, and a layer, on said spacer layer, having no granular structure and comprising alternating films of Co or an alloy thereof and Pd or alternating films of Co or an alloy thereof and Pt, forming said ferromagnetic layer on said underlayer by sputtering in an argon gas atmosphere and then forming said layer having no granular structure by sputtering in an argon gas atmosphere at a gas pressure lower than a gas pressure used when forming said ferromagnetic layer,

said method thereby manufacturing said perpendicular magnetic recording disk comprising, on said substrate, said soft magnetic layer, said underlayer, said ferromagnetic layer having the granular structure, said spacer layer, and said layer having no granular structure in this order,

wherein the layer having no granular structure comprises at least two films of Co or an alloy thereof and at least two films of Pd or Pt.

Assignments (8)