Perpendicular magnetic recording medium having FCC seed layers
According to one embodiment, a perpendicular magnetic recording medium includes at least one soft magnetic underlayer above a substrate, a seed layer above the at least one soft magnetic underlayer, an intermediate layer above the seed layer, a magnetic recording layer above the intermediate layer, and an overcoat layer above the magnetic recording layer, wherein the seed layer includes a second seed layer above a first seed layer. In another embodiment, the seed layer is a multilayered structure of at least two cycles of a unit of layered film which includes a first seed layer and a second seed layer. The first seed layer includes a non-magnetic alloy having a Face-Centered-Cubic (FCC) structure, and the second seed layer includes a soft magnetic alloy having a FCC structure. Other structures are also disclosed, according to more embodiments.
1. A perpendicular magnetic recording medium, comprising:
at least one soft magnetic underlayer above a substrate;
a seed layer above the at least one soft magnetic underlayer;
an intermediate layer above the seed layer;
a magnetic recording layer above the intermediate layer; and
an overcoat layer above the magnetic recording layer,
wherein the seed layer includes four seed layers: a fourth seed layer above a third seed layer, the third seed layer being above a second seed layer, and the second seed layer being above a first seed layer,
wherein the first seed layer and the third seed layer include a non-magnetic alloy having a Face-Centered-Cubic (FCC) structure, and
wherein the second seed layer and the fourth seed layer include a soft magnetic alloy having a FCC structure.
2. The perpendicular magnetic recording medium of claim 1 , wherein the first seed layer and the third seed layer include a nickel-tungsten (NiW) alloy.
3. The perpendicular magnetic recording medium of claim 2 , wherein the tungsten (W) content of the NiW alloy is less than about 20 atomic percent (at. %).
4. The perpendicular magnetic recording medium of claim 2 , wherein the second seed layer and the fourth seed layer include an alloy having a main component of nickel-iron (NiFe) or cobalt-iron (CoFe).
5. The perpendicular magnetic recording medium of claim 4 , wherein the second seed layer and the fourth seed layer include at least one of tungsten (W), vanadium (V), and tantalum (Ta).
6. The perpendicular magnetic recording medium of claim 1 , wherein the first seed layer and the third seed layer include a nickel-tungsten-chromium (NiWCr) alloy.
7. The perpendicular magnetic recording medium of claim 1 , wherein a combined film thickness of the first seed layer and the third seed layer is in a range from about 2 nm to about 8 nm, and wherein a combined film thickness of the second seed layer and the third seed layer is in a range from about 2 nm to about 7 nm.
8. The perpendicular magnetic recording medium of claim 1 , wherein the intermediate layer includes ruthenium (Ru) or an alloy thereof.
9. A disk drive system, comprising:
the perpendicular magnetic recording medium of claim 1 ;
at least one magnetic head for writing to the magnetic medium;
a slider for supporting the at least one magnetic head; and
a control unit coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.
10. A perpendicular magnetic recording medium, comprising:
at least one soft magnetic underlayer above a substrate;
a seed layer above the at least one soft magnetic underlayer;
an intermediate layer above the seed layer;
a magnetic recording layer above the intermediate layer; and
an overcoat layer above the magnetic recording layer,
wherein the seed layer is a multilayered structure of at least two cycles of a unit of layered film which includes a first seed layer and a second seed layer,
wherein each of the first seed layers include a non-magnetic alloy having a Face-Centered-Cubic (FCC) structure, and
wherein each of the second seed layers include a soft magnetic alloy having a FCC structure.
11. The perpendicular magnetic recording medium of claim 10 , wherein each of the first seed layers include a nickel-tungsten (NiW) alloy.
12. The perpendicular magnetic recording medium of claim 11 , wherein the NiW alloy includes less than about 20 atomic percent (at. %) NiW.
13. The perpendicular magnetic recording medium of claim 11 , wherein each of the second seed layers is an alloy having a main component of NiFe or CoFe.
14. The perpendicular magnetic recording medium described in claim 13 , wherein each of the second seed layers also include at least one of W, V, and Ta.
15. The perpendicular magnetic recording medium of claim 10 , wherein each of the first seed layers include a nickel-tungsten-chromium (NiWCr) alloy.
16. The perpendicular magnetic recording medium of claim 10 , wherein a combined film thickness of all of the first seed layers is in a range from about 1 nm to about 4 nm, and wherein a combined film thickness of all of the second seed layers is in a range from about 1 nm to about 4 nm.
17. The perpendicular magnetic recording medium of claim 10 , wherein the intermediate layer includes ruthenium (Ru) or an alloy thereof.
18. A disk drive system, comprising:
the perpendicular magnetic recording medium of claim 10 :
at least one magnetic head for writing to the magnetic medium;
a slider for supporting the at least one magnetic head; and
a control unit coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.
19. The perpendicular magnetic recording medium of claim 10 , wherein a number of cycles of the unit of layered film is no more than four.
20. A perpendicular magnetic recording medium, comprising:
at least one soft magnetic underlayer above a substrate;
a non-magnetic seed layer above the soft magnetic underlayer;
a magnetic seed layer above the non-magnetic seed layer, the non-magnetic seed layer being positioned between the soft magnetic underlayer and the magnetic seed layer,
an intermediate layer above the seed layers;
a magnetic recording layer above the intermediate layer; and
an overcoat layer above the magnetic recording layer,
wherein the non-magnetic seed layer includes a non-magnetic alloy having a Face-Centered-Cubic (FCC) structure,
wherein the non-magnetic seed layer has a thickness in a range of 1 to 4 nm,
wherein the magnetic seed layer includes a soft magnetic alloy having a FCC structure,
wherein the magnetic seed layer has a thickness in a range of 1 to 4 nm.