Tilted media for hard disk drives and magnetic data storage devices

• US 7,144,640 B2
• Filed: 08/01/2003
• Issued: 12/05/2006
• Est. Priority Date: 08/01/2003
• Status: Expired due to Fees

• Current Assignee: Agency For Science Technology and Research
• Original Assignee: Agency For Science Technology and Research
• Inventors: Zhao, Haibao, Hee, Ching Hian, Wang, Jian Ping
• Primary Examiner(s): RICKMAN, HOLLY C
• Application Number:
  US10/632,522
• Publication Number:
  US 20050084715A1
• Time in Patent Office: 1,222 Days
• Field of Search: 428/827, 428/828, 428/830
• US Class Current: 428/827
• CPC Class Codes: G11B 5/656 containing Co containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658
• CPC Class Codes: G11B 5/66 the record carriers consisting of several layers

Abstract

A digital storage medium for use in data storage devices has two magnetic layers where the respective easy axes of the magnetic moments in the two layers are perpendicular to each other. Exchange coupling of the magnetic moments in the magnetic layers produces a resultant magnetic moment that is tilted out of the plane of the digital storage medium. The resultant magnetic moment of the medium allows the use of either a ring head, a single pole head, or a head that generates a field tilted at an angle for write operations.

Claims

1. A digital storage medium, comprising:

a substrate;

a first magnetic layer disposed over the substrate, wherein the first magnetic layer has a first magnetic moment having a tilted easy axis;

a second magnetic layer disposed over the first magnetic layer, wherein the second magnetic layer has a second magnetic moment having a tilted easy axis; and

an overcoat layer disposed over the second magnetic layer,

wherein the first magnetic layer has a perpendicular magnetic anisotropy and the second magnetic layer has a longitudinal anisotropy.

3. The digital storage medium of claim 1 or 2, wherein the magnetic layer with the longitudinal anisotropy includes a material selected from a group consisting of cobalt (Co), iron (Fe), nickel (Ni), and alloys thereof.

4. The digital storage medium of claim 1, wherein the magnetic layer with the perpendicular anisotropy includes a material selected from a group consisting of cobalt, iron, and alloys thereof.

6. The digital storage medium of claim 4, wherein the magnetic layer is formed from a single layer of alloys selected from a group consisting of cobalt-platinum (CoPt), cobalt-palladium (CoPd), cobalt-chromium-platinum (CoCrPt), cobalt-chromium-platinum-boron (CoCrPtB), cobalt-chromium-platinum-tantalum (CoCrPtTa), cobalt-chromium-platinum-niobium (CoCrPtNb), and iron-platinum (FePt).

8. The digital storage medium of claim 4, wherein the magnetic layer is formed from multiple layers of ferromagnetic materials selected from a group consisting of cobalt with palladium as a spacer layer (Co/Pd), cobalt with platinum as a spacer layer (Co/Pt), a cobalt alloy wilt palladium as a spacer layer, and a cobalt alloy with platinum as a spacer layer.

10. The digital storage medium of claim 6, wherein the alloys are doped with non-ferromagnetic materials selected from a group consisting of silicon oxide and silicon nitride.

15. The digital storage medium of claim 1, further comprising an interlayer disposed between the first magnetic layer and the second magnetic layer.

16. The digital storage medium of claim 15, wherein the interlayer includes a magnetization material selected from a group consisting of cobalt, nickel, iron, alloys of cobalt, alloys of nickel, and alloys of iron.

17. The digital storage medium of claim 15, wherein the interlayer includes a non-magnetic material selected from a group consisting of ruthenium (Ru), rhodium (Rh), chromium (Cr), copper (Cu), iridium (Ir), and alloys thereof.

2. A digital storage medium, comprising:

a substrate;

a first magnetic layer disposed over the substrate, wherein the first magnetic layer has a first magnetic moment having a tilted easy axis;

a second magnetic layer disposed over the first magnetic layer, wherein the second magnetic layer has a second magnetic moment having a tilted easy axis; and

an overcoat layer disposed over the second magnetic layer,

wherein the first magnetic layer has a longitudinal magnetic anisotropy and the second magnetic layer has a perpendicular anisotropy.

5. The digital storage medium of claim 2, wherein the magnetic layer with the perpendicular anisotropy includes a material selected from a group consisting of cobalt, iron, and alloys thereof.

7. The digital storage medium of claim 5, wherein the magnetic layer is formed from a single layer of alloys selected from a group consisting of cobalt-platinum (CoPt), cobalt-palladium (CoPd), cobalt-chromium-platinum (CoCrPtTa), cobalt-chromium-platinum-boron (CoCrPtB), cobalt-chromium-platinum-tantalum (CoCrPtTa), cobalt-chromium-platinum-niobium (CoCrPtNb), and iron-platinum (FePt).

9. The digital storage medium of claim 5, wherein the magnetic layer is formed from multiple layers of ferromagnetic materials selected from a group consisting of cobalt with palladium as a spacer layer (Co/Pd), cobalt with platinum as a spacer layer (Co/Pt), a cobalt alloy with palladium as a spacer layer and a cobalt alloy with platinum as a spacer layer.

11. The digital storage medium of claim 7, wherein the alloys are doped with non-ferromagnetic materials selected from a group consisting of silicon oxide and silicon nitride.

18. The digital storage medium of claim 2, further comprising an interlayer disposed between the first magnetic layer and the second magnetic layer.

19. The digital storage medium of claim 18, wherein the interlayer includes a magnetization material selected from a group consisting of cobalt, nickel, iron, alloys of cobalt, alloys of nickel, and alloys of iron.

20. The digital storage medium of claim 18, wherein the interlayer includes a non-magnetic material selected from a group consisting of ruthenium (Ru), rhodium (Rh), chromium (Cr), copper (Cu), iridium (Ir), and alloys thereof.

12. A digital storage medium, comprising:

a substrate;

a first magnetic layer disposed over the substrate, wherein the first magnetic layer has a first magnetic moment having a tilted easy axis;

a second magnetic layer disposed over the first magnetic layer, wherein the second magnetic layer has a second magnetic moment having a tilted easy axis;

an interlayer disposed between the first magnetic layer and the second magnetic layer; and

an overcoat layer disposed over the second magnetic layer.

13. The digital storage medium of claim 12, wherein the interlayer includes a magnetization material selected from a group consisting of cobalt, nickel, iron, alloys of cobalt, alloys of nickel, alloys of iron.

14. The digital storage medium of claim 12, wherein the interlayer includes a non-magnetic material selected from a group consisting of ruthenium (Ru), rhodium (Rh), chromium (Cr), copper (Cu), iridium (Ir), and alloys thereof.