Magnetic recording disk with composite perpendicular recording layer

• US 6,468,670 B1
• Filed: 01/19/2000
• Issued: 10/22/2002
• Est. Priority Date: 01/19/2000
• Status: Expired due to Term

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Schabes, Manfred Ernst, Ikeda, Yoshihiro, Takano, Kentaro, Weller, Dieter Klaus, Sonobe, Yoshiaki
• Primary Examiner(s): Thibodeau, Paul
• Assistant Examiner(s): Bernatz, Kevin M.
• Application Number:
  US09/487,234
• Time in Patent Office: 1,007 Days
• Field of Search: 428/611, 428/663, 428/669, 428/680, 428/681, 428/900, 428/694.TS, 428/694.TM, 428/670, 428/65.3, 428/65.7
• US Class Current: 428/611
• CPC Class Codes: G11B 5/66 the record carriers consisting of several layers
• CPC Class Codes: G11B 5/667 including a soft magnetic layer
• CPC Class Codes: G11B 5/672 having different compositions in a plurality of magnetic layers, e.g. layer compositions having differing elemental components or differing proportions of elements
• CPC Class Codes: G11B 5/674 having differing macroscopic or microscopic structures, e.g. differing crystalline lattices, varying atomic structures or differing roughnesses
• CPC Class Codes: G11B 5/678 having three or more magnetic layers
• CPC Class Codes: G11B 5/7368 Non-polymeric layer under the lowermost magnetic recording layer base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/7371 Non-magnetic single underlayer comprising nickel
• CPC Class Codes: G11B 5/7373 Non-magnetic single underlayer comprising chromium
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12868 Group IB metal-base component alternative to platinum group metal-base component [e.g., precious metal, etc.]
• CPC Class Codes: Y10T 428/12875 Platinum group metal-base component

Abstract

A composite perpendicular magnetic recording disk has two distinct magnetic layers formed on the disk substrate, each with strong perpendicular magnetic anisotropy, that are strongly exchange coupled perpendicularly to each other across their interface. The first layer is a CoCr granular layer formed on a growth-enhancing sublayer, such as titanium, so as to have strong perpendicular magnetic anisotropy. The second layer is a continuous layer, preferably a continuous multilayer of Co/Pt or Co/Pd palladium formed on top of the granular layer. An interface layer, such as a layer of platinum or palladium, depending on whether the top multilayer is Co/Pt or Co/Pd, respectively, may be located between the two layers to enhance the growth of the continuous multilayer.

Claims

1. A perpendicular magnetic recording disk comprising:

a substrate having a substantially planar first surface;

a granular layer of an alloy comprising cobalt and chromium on said first surface, the granular layer having perpendicular magnetic anisotropy; and

a continuous layer of material on said first surface in contact with the granular layer at an interface and having perpendicular magnetic anisotropy, the material of the continuous layer being exchange coupled perpendicularly with the granular layer at the interface between the granular layer and the continuous layer, the continuous layer comprising a multilayer of alternating first and second films, the first film consisting essentially of cobalt and the second film being selected from the group consisting of platinum and palladium.

2. The disk according to claim 1 wherein the granular layer alloy further comprises platinum in an amount up to approximately 10 atomic %.

3. The disk according to claim 1 wherein the granular layer alloy further comprises boron in an amount up to approximately 25 atomic %.

4. The disk according to claim 1 wherein the granular layer alloy further comprises tantalum in an amount up to approximately 10 atomic %.

5. The disk according to claim 1 wherein the granular layer alloy further comprises niobium in an amount up to approximately 10 atomic %.

6. The disk according to claim 1 wherein the first film is a cobalt alloy comprising cobalt and one or more of elements selected from the group consisting of tantalum, platinum, chromium and boron.

7. The disk according to claim 1 wherein the granular layer is located between the substrate and the multilayer and further comprising an interface layer of material identical to the material of the second film, the interface layer being formed directly on the granular layer and the multilayer being formed directly on the interface layer.

8. The disk according to claim 1 wherein the granular layer is located between the substrate and the multilayer and the multilayer is located on top of the granular layer.

9. The disk according to claim 8 further comprising a growth enhancing sublayer of material selected from the group consisting of Ti, TiCr, C, NiAl, SiO₂ and CoCr (wherein Cr is between 35 and 40 atomic percent) located between the substrate and the granular layer, and wherein the granular layer is formed directly on the growth enhancing sublayer.

10. The disk according to claim 8 further comprising a soft magnetically permeable underlayer located between the substrate and the granular layer.

11. The disk according to claim 10 wherein the soft magnetically permeable underlayer is selected from the group consisting of NiFe, FeAlSi, FeTaN, FeN, CoFeB and CoZrNb.

12. A perpendicular magnetic recording disk comprising:

a substrate;

a soft magnetically permeable underlayer on the substrate;

a growth enhancing sublayer of material selected from the group consisting of Ti, TiCr, C, NiAl, SiO₂ and CoCr (wherein Cr is between 35 and 40 atomic percent) on the soft underlayer;

a granular layer of an alloy comprising cobalt and chromium, the granular layer having perpendicular magnetic anisotropy and being formed directly on the growth enhancing sublayer; and

a multilayer having perpendicular magnetic anisotropy formed on the granular layer and comprising alternating first and second films, the first film consisting essentially of cobalt and the second film being selected from the group consisting of platinum and palladium, the multilayer being exchange coupled perpendicularly with the granular layer at the interface between the granular layer and the multilayer.

13. The disk according to claim 12 wherein the soft magnetically permeable underlayer is selected from the group consisting of NiFe, FeAlSi, FeTaN, FeN, CoFeB and CoZrNb.

14. The disk according to claim 12 wherein the granular layer alloy further comprises platinum in an amount up to approximately 10 atomic %.

15. The disk according to claim 12 wherein the granular layer alloy further comprises boron in an amount up to approximately 25 atomic %.

16. The disk according to claim 12 wherein the granular layer alloy further comprises tantalum in an amount up to approximately 10 atomic %.

17. The disk according to claim 12 wherein the granular layer alloy further comprises niobium in an amount up to approximately 10 atomic %.

18. The disk according to claim 12 wherein the first film of the multilayer is a cobalt alloy comprising cobalt and one or more of elements selected from the group consisting of tantalum, platinum, chromium and boron.

19. The disk according to claim 12 further comprising an interface layer directly on the granular layer and wherein the multilayer is directly on the interface layer, the interface layer being formed of a material identical to the material of the second film of the multilayer.