Magnetic recording medium and manufacture method therefor

1. A magnetic recording medium, comprising:

a protective film;

a nonmagnetic substrate;

a nonmagnetic base layer having a body-centered cubic structure and a (200) plane comprising a crystal-orientation parallel with a surface of the protective film;

a nonmagnetic intermediate layer having a hexagonal close-packed structure and a (110) plane comprising a crystal-orientation parallel with the surface of the protective, film;

a magnetic layer having a granular structure comprising hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains;

a liquid lubricant layer, wherein the nonmagnetic base layer, the nonmagnetic intermediate layer, the magnetic layer, the protective film, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate, and

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane.

2. A magnetic recording medium, comprising:

a protective film;

a nonmagnetic substrate;

a nonmagnetic base layer having a body-centered cubic structure and a (200) plane comprising a crystal-orientation parallel with a surface of the protective film;

a nonmagnetic intermediate layer having a hexagonal close-packed structure and a (110) plane comprising a crystal-orientation parallel with the surface of the protective film;

a magnetic layer having a granular structure comprising hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains;

a liquid lubricant layer, wherein the nonmagnetic base layer, the nonmagnetic intermediate layer, the magnetic layer, the protective film, and the liquid lubricant layer are sequentially stacked on the nonmagnetic substrate; and

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane,

wherein the nonmagnetic base layer comprises a material selected from the group of alloys and elements consisting of W, Mo, V and alloys of W, Mo, Cr, or V with 10-60 at % Ti.

3. The magnetic recording medium as recited in claim 2 , wherein the nonmagnetic orientation control layer is at least one of Mg, Ti, V, or Mn, or a carbide or a nitride of at least one of Ti, Zr, Hf, Nb, Ta, Mo, or W.

4. The magnetic recording medium as recited in claim 3 , further comprising:

an amorphous seed layer formed between the nonmagnetic orientation control layer and the substrate.

5. The magnetic recording medium as recited in claim 4 , wherein the seed layer is a Ni layer comprising 10-40 at % P or a Si layer containing 25-55 at % oxygen.

6. The magnetic recording medium as recited in claim 5 , wherein the nonmagnetic grain boundaries in the magnetic layer comprise an oxide or a nitride of at least one of Cr, Co, Si, Al, Ta, Hf, or Zr.

7. The magnetic recording medium as recited in claim 6 , wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo, or Cu.

8. The magnetic recording medium as recited in claim 1 , wherein the nonmagnetic grain boundaries in the magnetic layer comprise an oxide or a nitride of at least one of Cr, Co, Si, Al, Ta, Hf, or Zr.

9. The magnetic recording medium as recited in claim 8 , wherein the nonmagnetic substrate is a crystallized glass, a chemically reinforced glass, or a synthetic resin.

10. The magnetic recording medium as recited in claim 1 , wherein the nonmagnetic intermediate layer comprises a material selected from the group at alloys and elements consisting of Ru, Ir, Rh, and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo, or Cu.

11. The magnetic recording medium as recited in claim 10 , wherein the nonmagnetic base layer comprises a material selected from the group of alloys and elements consisting of W, Mo, V and alloys of W, Mo, Cr, or V with 10-60 at % Ti.

12. The magnetic recording medium as recited in claim 1 , wherein the nonmagnetic substrate is a crystallized glass, a chemically reinforced glass, or a synthetic resin.

13. A manufacturing method of a magnetic recording medium, comprising:

sequentially stacking on a nonmagnetic substrate a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, a protective film, and a liquid lubricant layer, wherein the nonmagnetic base layer comprises a body-centered cubic structure and a (200) plane having a crystal-orientation parallel with a surface of the protective film, the nonmagnetic intermediate layer comprises a hexagonal close-packed structure and a (110) plane having a crystal-orientation parallel with the surface of the protective film, and the magnetic layer comprises a granular structure having hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains;

executing a film formation process without heating the nonmagnetic substrate in advance; and

forming a nonmagnetic orientation control layer of a simple cubic structure between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane.

14. The method as recited in claim 13 , wherein the nonmagnetic base layer comprises a material selected from the group of alloys and elements consisting of W, Mo, and alloys of W, Mo, Cr, or V having 10-60 at % Ti.

15. The method as recited in claim 13 , wherein the nonmagnetic orientation control layer is an oxide of at least one of Mg, Ti, V, or Mn, or a carbide or a nitride of at least one of Ti, Zr, Hf, Nb, Ta, Mo, or W.

16. The method as recited in claim 15 , further comprising:

forming an amorphous seed layer between the nonmagnetic orientation control layer and the substrate.

17. The method as recited in claim 16 , wherein the seed layer is a Ni layer comprising 10-40 at % P or a Si layer containing 25-55 at % oxygen.

18. A manufacturing method of a magnetic recording medium, comprising:

sequentially stacking on a nonmagnetic substrate a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, a protective film, and a liquid lubricant layer, wherein the nonmagnetic base layer comprises a body-centered cubic structure and a (200) plane having a crystal-orientation parallel with a surface of the protective film, the nonmagnetic intermediate layer comprises a hexagonal close-packed structure and a (110) plane having a crystal-orientation parallel with the surface of the protective film, and the magnetic layer comprises a granular structure having hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains; and

executing a film formation process without heating the nonmagnetic substrate in advance, forming a nonmagnetic orientation control layer of a simple cubic structure between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane,

wherein the nonmagnetic grain boundaries in the magnetic layer consists of an oxide or a nitride of at least one of Cr, Co, Si, Al, Ta, Hf, or Zr.

19. A manufacturing method of a magnetic recording medium, comprising:

sequentially stacking on a nonmagnetic substrate a nonmagnetic base layer, a nonmagnetic intermediate layer, a magnetic layer, a protective film, and a liquid lubricant layer, wherein the nonmagnetic base layer comprises a body-centered cubic structure and a (200) plane having a crystal-orientation parallel with a surface of the protective film, the nonmagnetic intermediate layer comprises a hexagonal close-packed structure and a (110) plane having a crystal-orientation parallel with the surface of the protective film, and the magnetic layer comprises a granular structure having hexagonal close-packed ferromagnetic crystal grains and oxide-based nonmagnetic grain boundaries surrounding the ferromagnetic crystal grains; and

executing a film formation process without heating the nonmagnetic substrate in advance,

wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu.

20. The method as recited in claim 13 , wherein the nonmagnetic substrate is a crystallized glass, a chemically reinforced glass, or a synthetic resin.

21. The magnetic recording medium as recited in claim 1 , wherein the nonmagnetic base layer comprises a material selected from the group of alloys and elements consisting of W, Mo, V and alloys of W, Mo, Cr, or V having 10-60 at % Ti and wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu.

22. The magnetic recording medium as recited in claim 1 , further comprising:

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane, wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu.

23. The magnetic recording medium as recited in claim 2 , further comprising:

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane, wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re, ad alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo, or Cu, and wherein the nonmagnetic orientation control layer is an oxide of at least one of Mg, Ti, V, or Mn, or a carbide or a nitride of at least one of Ti, Zr, Hf, Nb, Ta, Mo, or W.

24. The magnetic recording medium as recited in claim 2 , further comprising:

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane, wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu; and

an amorphous seed layer formed between the nonmagnetic orientation control layer and the substrate.

25. The magnetic recording medium as recited in claim 2 , further comprising:

a nonmagnetic orientation control layer of a simple cubic structure formed between the nonmagnetic base layer and the substrate, and the crystal-orientation parallel with the film surface is the (110) plane, wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu; and

a amorphous seed layer formed between the nonmagnetic orientation control layer and the substrate,

wherein the seed layer is a Ni layer comprising 10-40 at % P or a Si layer containing 25-55 at % oxygen.

26. The magnetic recording medium as recited in claim 1 , wherein the nonmagnetic intermediate layer comprises a material selected from the group of alloys and elements consisting of Ru, Ir, Rh, Re and alloys of Ru, Ir, Rh, or Re containing 10-60 at % Ti, C, W, Mo or Cu, and wherein the nonmagnetic grain boundaries in the magnetic layer comprise an oxide or a nitride of at least one of Cr, Co, Si, Al, Ta, Hf, or Zr.