Magnetic media design with multiple non-magnetic exchange control layers and graded magnetic sublayers
Magnetic media including a magnetic recording layer structure formed of alternating magnetic recording sublayers and non-magnetic exchange control sublayers. The magnetic recording layer structure may include at least one magnetic recording sublayer formed to include a pair of thin films, with the films having different concentrations of platinum, ruthenium, and/or oxide segregants. That is, the sublayer has a “dual layer” structure. The dual layer structure can provide a gradient in magnetic anisotropy, saturation magnetization, and/or intergranular magnetic exchange coupling across the sublayer. In some examples, the film nearer to the substrate of the magnetic media has a higher platinum concentration than the other film. In one aspect, the magnetic media includes the substrate and the magnetic recording layer structure on the substrate, with the structure including six magnetic recording sublayers. In another aspect, a method of fabricating magnetic media with such structures is provided.
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 at least one of the magnetic recording sublayers comprises first and second films, with the first film nearer to the substrate than the second film, wherein each of the first and second films comprises both Pt and Ru, with the first film having a higher concentration of Pt than the second film, and with the first film having a lower concentration of Ru than the second film.
2. The magnetic medium of claim 1 , wherein the first film further comprises Co and Cr with a first segregant and the second film further comprises Co and B with a second segregant.
3. The magnetic medium of claim 2 , wherein the first and second segregants comprise one or more of B 2 O 3 , SiO 2 , Cr 2 O 3 , TiO 2 , or CoO.
4. The magnetic medium of claim 1 , wherein the first film further comprises Co, Cr, B 2 O 3 , SiO 2 , TiO 2 , and CoO and the second film further comprises Co, B, SiO 2 , Cr 2 O 3 , and CoO.
5. The magnetic medium of claim 1 , wherein the first film further comprises Co, Cr, B 2 O 3 , SiO 2 , TiO 2 , and Co 3 O 4 and the second film also further comprises Co, Cr, B 2 O 3 , SiO 2 , TiO 2 , and Co 3 O 4 .
6. The magnetic medium of claim 1 , wherein the at least one of the magnetic recording sublayers comprising the first and second films comprises a magnetic recording sublayer closest to the substrate.
7. The magnetic medium of claim 1 , wherein the at least one of the magnetic recording sublayers comprising the first and second films comprises a magnetic recording sublayer farthest from the substrate.
8. The magnetic medium of claim 1 , wherein the magnetic recording layer structure comprises fewer than six of the magnetic recording sublayers.
9. The magnetic medium of claim 1 , wherein the magnetic recording layer structure comprises at least six of the magnetic recording sublayers.
10. The magnetic medium of claim 1 , wherein the at least one of the magnetic recording sublayers comprising the first and second films further comprises at least a third film, wherein the third film comprises both Pt and Ru, wherein a concentration of the Pt in the third film is between the respective concentrations of Pt in the first and second films, and wherein a concentration of the Ru in the third film is between the respective concentrations of Ru in the first and second films.
11. The magnetic medium of claim 1 , wherein the first film further comprises an oxide segregant that has a different concentration than a concentration of an oxide segregant of the second film.
12. A magnetic recording device, comprising the magnetic medium of claim 1 and a recording head configured to write information to the magnetic medium.
13. 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 sublayers comprise a first magnetic recording sublayer nearest to the substrate, a second magnetic recording sublayer farthest from the substrate, and one or more intermediate magnetic recording sublayers, and wherein the first and second magnetic recording sublayers are thicker than each of the one or more intermediate magnetic recording sublayers; and
wherein at least one of the first and second magnetic recording sublayers comprises first and second films, each of the first and second films comprising both Pt and Ru, with the first film having a higher concentration of Pt than the second film, and with the first film having a lower concentration of Ru than the second film.
14. The magnetic medium of claim 13 , wherein the first film is nearer to the substrate than the second film.
15. The magnetic medium of claim 13 , wherein the first magnetic recording sublayer nearest to the substrate and the second magnetic recording sublayer farthest from the substrate each comprise two or more films having different concentrations of Pt.
16. The magnetic medium of claim 13 , wherein the first magnetic recording sublayer nearest to the substrate and the second magnetic recording sublayer farthest from the substrate are each at least twenty angstroms thick, and wherein the one or more intermediate magnetic recording sublayers are each less than twenty angstroms thick.
17. A magnetic recording device comprising the magnetic medium of claim 13 and a recording head configured to write information to the magnetic medium.
18. 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 at least one of the magnetic recording sublayers is formed to include first and second films, with the first film nearer to the substrate than the second film, wherein each of the first and second films is formed to comprise both Pt and Ru, with the first film having a higher concentration of Pt than the second film, and with the first film having a lower concentration of Ru than the second film.
19. The method of claim 18 , wherein the first film is formed to further comprise Co and Cr with a first segregant and the second film is formed to further comprise Co and B with a second segregant.
20. The method of claim 18 , wherein the at least one of the magnetic recording sublayers comprises a magnetic recording sublayer closest to the substrate.
21. The method of claim 18 , wherein the at least one of the magnetic recording sublayers comprises a magnetic recording sublayer farthest from the substrate.
22. The method of claim 18 , wherein the first film is formed with a higher total concentration of oxides than a total concentration of oxides of the second film.
23. The method of claim 18 , wherein the first film comprises a first oxide segregant, and wherein the second film comprises a second oxide segregant different from the first oxide segregant.
24. The magnetic medium of claim 1 , wherein the first film and the second film are not separated by a non-magnetic layer.
25. The magnetic medium of claim 1 , wherein the at least one of the magnetic recording sublayers comprises a topmost magnetic recording sublayer of a stack of at least six magnetic recording sublayers.
26. The magnetic medium of claim 1 , wherein the first film further comprises an oxide segregant and the second film further comprises a different oxide segregant.
27. The method of claim 18 , wherein the first film and the second film are not separated by a non-magnetic layer.
28. The method of claim 18 , wherein the at least one of the magnetic recording sublayers is formed as a topmost magnetic recording sublayer of a stack of at least six magnetic recording sublayers.