MAGNETIC MEDIA DESIGN WITH MULTIPLE NON-MAGNETIC EXCHANGE CONTROL LAYERS

• US 20190325905A1
• Filed: 04/20/2018
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Tang, Kai, Ghaderi, Arien Michael, Li, Tuqiang, Lo, Chi Ho
• Granted Patent: US 10,923,147 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/678 having three or more magnetic layers
• CPC Class Codes: G11B 5/82 Disk carriers
• CPC Class Codes: G11B 5/84 Processes or apparatus specially adapted for manufacturing record carriers
• CPC Class Codes: G11B 5/851 Coating a support with a magnetic layer by sputtering

Abstract

Magnetic media including a magnetic recording layer structure of at least six magnetic recording sublayers and at least six non-magnetic exchange control sublayers in an alternating pattern are provided. The magnetic recording layer structure includes a gradient of platinum content across the magnetic recording sublayers such that a top magnetic recording sublayer has a lowest platinum content and a bottom magnetic recording sublayer has a highest platinum content. In one such case, the magnetic media includes a substrate and the magnetic recording layer structure on the substrate. In another case, a method of fabricating such magnetic media is provided.

Claims

1. A magnetic medium, comprising:

a substrate; and

a magnetic recording layer structure on the substrate, the magnetic recording layer structure comprising an alternating pattern of magnetic recording sublayers and non-magnetic exchange control sublayers;

wherein the magnetic recording layer structure comprises at least six of the magnetic recording sublayers and at least six of the non-magnetic exchange control sublayers; and

wherein the magnetic recording layer structure further comprises a gradient of platinum content across the magnetic recording sublayers such that a bottom magnetic recording sublayer of the magnetic recording sublayers that is nearest the substrate comprises a highest platinum content among the magnetic recording sublayers and a top magnetic recording sublayer of the magnetic recording sublayers that is furthest from the substrate comprises a lowest platinum content among the magnetic recording sublayers.

2. The magnetic medium of claim 1, wherein the lowest platinum content is between about twelve and eighteen atomic percent and the highest platinum content is between about nineteen and twenty-four atomic percent.

3. The magnetic medium of claim 1, wherein each additional magnetic recording sublayer between the top magnetic recording sublayer and the bottom magnetic recording sublayer comprises a respective platinum content equal to or less than a respective adjacent platinum content of a respective adjacent magnetic recording sublayer closer to the substrate than the additional magnetic recording sublayer.

4. The magnetic medium of claim 3, wherein each of the magnetic recording sublayers comprises a Ku equal to or less than the respective adjacent magnetic recording layer below the magnetic recording sublayer.

5. The magnetic medium of claim 1, wherein the magnetic recording layer structure comprises:

a first magnetic recording sublayer on the substrate, wherein the first magnetic recording sublayer comprises the bottom magnetic recording sublayer;

a first non-magnetic exchange control sublayer on the first magnetic recording sublayer;

a second magnetic recording sublayer on the first non-magnetic exchange control sublayer;

a second non-magnetic exchange control sublayer on the second magnetic recording sublayer;

a third magnetic recording sublayer on the second non-magnetic exchange control sublayer;

a third non-magnetic exchange control sublayer on the third magnetic recording sublayer;

a fourth magnetic recording sublayer on the third non-magnetic exchange control sublayer;

a fourth non-magnetic exchange control sublayer on the fourth magnetic recording sublayer;

a fifth magnetic recording sublayer on the fourth non-magnetic exchange control sublayer;

a fifth non-magnetic exchange control sublayer on the fifth magnetic recording sublayer;

a sixth magnetic recording sublayer on the fifth non-magnetic exchange control sublayer, wherein the sixth magnetic recording sublayer comprises the top magnetic recording sublayer; and

a sixth non-magnetic exchange control sublayer on the sixth magnetic recording sublayer.

6. The magnetic medium of claim 5, wherein the magnetic recording layer structure further comprises:

a capping layer on the sixth non-magnetic exchange control sublayer.

7. The magnetic medium of claim 5, wherein the fifth magnetic recording sublayer comprises a fifth platinum content greater than the lowest platinum content of the top magnetic recording sublayer.

8. The magnetic medium of claim 7, wherein the second magnetic recording sublayer comprises a second platinum content less than the highest platinum content of the bottom magnetic recording sublayer and greater than the fifth platinum content of the fifth magnetic recording sublayer.

9. The magnetic medium of claim 8, wherein the third magnetic recording sublayer comprises a third platinum content equal to the second platinum content of the second magnetic recording sublayer.

10. The magnetic medium of claim 1, wherein each of the magnetic recording sublayers further comprises a cobalt alloy comprising platinum and at least one oxide segregant.

11. The magnetic medium of claim 10, wherein each of the magnetic recording sublayers further comprises one or more materials selected from the group consisting of Cr, B, Ru, and combinations thereof.

12. The magnetic medium of claim 10, wherein the at least one oxide segregant comprises one or more materials selected from the group consisting of CoO, Cr₂O₃, TiO₂, Co₃O₄, B₂O₃, SiO₂, and combinations thereof.

13. The magnetic medium of claim 12, wherein the top magnetic recording sublayer comprises TiO₂.

14. The magnetic medium of claim 1, wherein the top magnetic recording sublayer and the bottom magnetic recording sublayer each comprise a first thickness and additional magnetic recording sublayers between the top magnetic recording sublayer and the bottom magnetic recording sublayer each comprise a second thickness less than the first thickness.

15. The magnetic medium of claim 13, wherein the first thickness is between twenty and fifty angstroms and the second thickness is between two and twenty angstroms.

16. The magnetic medium of claim 1, wherein the magnetic medium comprises a perpendicular magnetic recording (PMR) medium, shingle-written magnetic recording (SMR) medium, or a microwave assisted magnetic recording (MAMR) medium.

17. A method for fabricating magnetic media, comprising:

providing a substrate;

forming a soft underlayer on the substrate;

forming a seed layer on the soft underlayer; and

forming a magnetic recording layer structure on the seed layer, the magnetic recording layer structure comprising an alternating pattern of magnetic recording sublayers and non-magnetic exchange control sublayers;

wherein the magnetic recording layer structure comprises at least six of the magnetic recording sublayers and at least six of the non-magnetic exchange control sublayers; and

wherein the magnetic recording layer structure further comprises a gradient of platinum content across the magnetic recording sublayers such that a bottom magnetic recording sublayer of the magnetic recording sublayers that is nearest to the substrate comprises a highest platinum content among the magnetic recording sublayers and a top magnetic recording sublayer of the magnetic recording sublayers that is furthest from the substrate comprises a lowest platinum content among the magnetic recording sublayers.

18. The method of claim 17, wherein:

the lowest platinum content is between about twelve and eighteen atomic percent and the highest platinum content is between about nineteen and twenty-four atomic percent; and

each additional magnetic recording sublayer between the top magnetic recording sublayer and the bottom magnetic recording sublayer comprises a respective platinum content equal to or less than a respective adjacent platinum content of a respective adjacent magnetic recording sublayer closer to the substrate than the additional magnetic recording sublayer.

19. The method of claim 17, wherein the forming the magnetic recording layer structure comprises:

forming a first magnetic recording sublayer on the substrate, wherein the first magnetic recording sublayer comprises the bottom magnetic recording sublayer;

forming a first non-magnetic exchange control sublayer on the first magnetic recording sublayer;

forming a second magnetic recording sublayer on the first non-magnetic exchange control sublayer;

forming a second non-magnetic exchange control sublayer on the second magnetic recording sublayer;

forming a third magnetic recording sublayer on the second non-magnetic exchange control sublayer;

forming a third non-magnetic exchange control sublayer on the third magnetic recording sublayer;

forming a fourth magnetic recording sublayer on the third non-magnetic exchange control sublayer;

forming a fourth non-magnetic exchange control sublayer on the fourth magnetic recording sublayer;

forming a fifth magnetic recording sublayer on the fourth non-magnetic exchange control sublayer;

forming a fifth non-magnetic exchange control sublayer on the fifth magnetic recording sublayer;

forming a sixth magnetic recording sublayer on the fifth non-magnetic exchange control sublayer, wherein the sixth magnetic recording sublayer comprises the top magnetic recording sublayer; and

forming a sixth non-magnetic exchange control sublayer on the sixth magnetic recording sublayer.

20. The method of claim 19, wherein the forming the magnetic recording layer structure further comprises:

forming a capping layer on the sixth non-magnetic exchange control sublayer.

21. The method of claim 19, wherein the fifth magnetic recording sublayer comprises a fifth platinum content greater than the lowest platinum content of the top magnetic recording sublayer.

22. The method of claim 21, wherein the second magnetic recording sublayer comprises a second platinum content less than the highest platinum content of the bottom magnetic recording sublayer and greater than the fifth platinum content of the fifth magnetic recording sublayer.

23. The method of claim 22, wherein the third magnetic recording sublayer comprises a third platinum content equal to the second platinum content of the second magnetic recording sublayer.

24. The method of claim 17, wherein each of the magnetic recording sublayers further comprises a cobalt alloy comprising platinum and at least one oxide segregant.

25. The method of claim 24, wherein each of the magnetic recording sublayers further comprises one or more materials selected from the group consisting of Cr, B, Ru, and combinations thereof.

26. The method of claim 24, wherein the at least one oxide segregant comprises one or more materials selected from the group consisting of CoO, Cr₂O₃, TiO₂, CO₃O₄, B₂O₃, SiO₂, and combinations thereof.

27. The method of claim 26, wherein the top magnetic recording sublayer comprises TiO₂.

28. The method of claim 17, wherein:

the top magnetic recording sublayer and the bottom magnetic recording sublayer each comprise a first thickness and additional magnetic recording sublayers between the top magnetic recording sublayer and the bottom magnetic recording sublayer each comprise a second thickness less than the first thickness; and

the first thickness is between twenty and fifty angstroms and the second thickness is between two and twenty angstroms.

29. The method of claim 17, wherein forming the magnetic recording layer structure on the seed layer further comprises:

depositing the magnetic recording layer structure on the seed layer at a temperature in a range from 50 degrees Celsius to 340 degrees Celsius.

30. The method of claim 17, wherein forming the magnetic recording layer structure on the seed layer further comprises:

depositing the magnetic recording layer structure utilizing direct current (DC) sputtering.