Intermediate layer for perpendicular magnetic recording medium with high permeability grain boundaries
View Patent ↗A perpendicular magnetic recording (PMR) media including a non-magnetic or superparamagnetic grain isolation magnetic anisotropy layer (GIMAL) to provide a template for initially well-isolated small grain microstructure as well as improvement of K u in core grains of a magnetic recording layer. The GIMAL composition may be adjusted to have lattice parameters similar to a bottom magnetic recording layer and to provide a buffer for reducing interface strains caused by lattice mismatch between the bottom magnetic recording layer and an underlying layer.
1. A perpendicular magnetic recording media, comprising:
a soft magnetic underlayer;
an intermediate layer disposed over the soft magnetic layer, wherein the intermediate layer includes a granular Ru structure separated by high permeability magnetic grain boundaries made from magnetic materials comprising CoIr, CoRu, NiO, Eu 2 Ru 2 O 7 , or Fe 2 O 3 ; and
a magnetic recording layer disposed over the intermediate layer.
2. The perpendicular magnetic recording media of claim 1 , wherein the magnetic grain boundaries allow the intermediate layer to have a smaller effective magnetic thickness than that of a pure Ru intermediate layer having an equivalent thickness, while maintaining a limited c-axis dispersion provided by the physical thickness of the Ru grains.
3. The perpendicular magnetic recording media of claim 2 , wherein the intermediate layer includes an effective magnetic thickness of between approximately 5 nm and 10 nm.
4. The perpendicular magnetic recording media of claim 2 , wherein the intermediate layer includes an effective magnetic thickness of less than 5 nm.
5. The perpendicular magnetic recording media of claim 1 , wherein the intermediate layer includes an Ru grain size of between approximately 4 nm and 10 nm.
6. The perpendicular magnetic recording media of claim 1 , wherein the intermediate layer includes an Ru grain size of between approximately 5 nm and 6 nm.
7. The perpendicular magnetic recording media of claim 6 , wherein the intermediate layer includes a grain boundary thickness of between approximately 1 nm and 1.5 nm.
8. The perpendicular magnetic recording media of claim 1 , wherein the soft magnetic underlayer includes a thin layer of Ru embedded therein.
9. The perpendicular magnetic recording media of claim 8 , wherein the thin layer of Ru embedded in the soft magnetic underlayer has a thickness between approximately 0.8 nm and 1.2 nm.
10. A media drive, comprising:
a head having a magneto-resistive read element; and
a perpendicular magnetic recording media operatively coupled to the head;
wherein the perpendicular magnetic recording media comprises:
a soft magnetic underlayer;
an intermediate layer disposed over the soft magnetic layer, wherein the intermediate layer includes a granular Ru structure separated by magnetic grain boundaries comprising CoIr, CoRu, NiO, Eu 2 Ru 2 O 7 , or Fe O 3 ; and
a magnetic recording layer disposed over the intermediate layer.
11. The media drive of claim 10 , wherein the magnetic grain boundaries allow the intermediate layer to have a smaller effective magnetic thickness than that of a pure Ru intermediate layer having an equivalent thickness, while maintaining a limited c-axis dispersion provided by the physical thickness of the Ru grains.
12. The media drive of claim 11 , wherein the intermediate layer includes an effective magnetic thickness of between approximately 5 nm and 10 nm.
13. The media drive of claim 11 , wherein the intermediate layer includes an effective magnetic thickness of less than 5 nm.
14. The media drive of claim 10 , wherein the intermediate layer includes an Ru grain size of between approximately 4 nm and 10 nm.
15. The media drive of claim 10 , wherein the intermediate layer includes an Ru grain size of between approximately 5 nm and 6 nm.
16. The media drive of claim 10 , wherein the intermediate layer includes a grain boundary thickness of between approximately 1 nm and 1.5 nm.
17. The media drive of claim 10 , wherein the soft magnetic underlayer includes a thin layer of Ru embedded therein.
18. The media drive of claim 17 , wherein the thin layer of Ru embedded in the soft magnetic underlayer has a thickness between approximately 0.8 nm and 1.2 nm.
19. A method, comprising:
depositing a soft magnetic underlayer over a substrate;
depositing an intermediate layer over the soft magnetic layer, the
intermediate layer having a granular Ru structure separated by magnetic grain boundaries comprising CoIr CoRu, NiO, Eu 2 Ru 2 O 7 , or Fe 2 O 3 ; and
depositing a magnetic recording layer over the intermediate layer.
20. The method of claim 19 , wherein the magnetic grain boundaries allow the intermediate layer to have a smaller effective magnetic thickness than that of a pure Ru intermediate layer having an equivalent thickness, while maintaining a limited c-axis dispersion provided by the physical thickness of the Ru grains.
21. The method of claim 20 , wherein the intermediate layer includes an effective magnetic thickness of between approximately 5 nm and 10 nm.
22. The method of claim 20 , wherein the intermediate layer includes an effective magnetic thickness of less than 5 nm.
23. The method of claim 19 , wherein the intermediate layer includes an Ru grain size of between approximately 4 nm and 10 nm.
24. The method of claim 19 , wherein the intermediate layer includes an Ru grain size of between approximately 5 nm and 6 nm.
25. The method of claim 19 , wherein the intermediate layer includes a grain boundary thickness of between approximately 1 nm and 1.5 nm.
26. The method of claim 19 , wherein the soft magnetic underlayer includes a thin layer of Ru embedded therein.
27. The method of claim 26 , wherein the thin layer of Ru embedded in the soft magnetic underlayer has a thickness between approximately 0.8 nm and 1.2 nm.