PERPENDICULAR MAGNETIC RECORDING MEDIUM HAVING AN OXIDE SEED LAYER AND RU ALLOY INTERMEDIATE LAYER

1 . A perpendicular magnetic recording medium, comprising:

a substrate;

a soft magnetic underlayer positioned above the substrate;

a seed layer structure positioned above the soft magnetic underlayer, the seed layer structure including a first seed layer and a second seed layer positioned above the first seed layer;

an interlayer structure positioned above the seed layer structure, the interlayer structure including a first interlayer, a second interlayer positioned above the first interlayer, and a third interlayer positioned above the second interlayer; and

a magnetic recording layer positioned above the interlayer structure;

wherein the second seed layer comprises a Ni alloy including at least one oxide,

wherein the first interlayer comprises a Ru alloy.

2 . The perpendicular magnetic recording medium as recited in claim 1 , wherein an amount of the oxide in the second seed layer is in a range between about 5 vol % to about 20 vol % based on a total volume of the second seed layer, and wherein the oxide is selected from a group consisting of: WO 3 , SiO 2 , TiO 2 , and Ta 2 O 5 .

3 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the Ni alloy of the second seed layer further includes, in addition to the oxide, at least one element selected from a group consisting of: Cr, W, V, Mo, Ta, and Nb.

4 . The perpendicular magnetic recording medium as recited in claim 1 , where a thickness of second seed layer is in a range between about 1 nm to about 4 nm.

5 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the first seed layer has a face centered cubic (fcc) structure, and comprises a Ni alloy including at least one element selected from a group consisting of: Cr, W, V, Mo, Ta and Nb.

6 . The perpendicular magnetic recording medium as recited in claim 5 , wherein the first seed layer does not include an oxide.

7 . The perpendicular magnetic recording medium as recited in claim 5 , wherein a thickness of the first seed layer is in a range between about 2 nm to about 7 nm.

8 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the first interlayer has a hexagonal close packed (hcp) structure.

9 . The perpendicular magnetic recording medium as recited in claim 8 , wherein the Ru alloy of the first interlayer includes an element selected from a group consisting of: Cr in a range from about 10 at % to about 40 at %, Ta in a range from about 10 at % to about 20 at %, W in a range from about 10 at % to about 40 at %, Mo in a range from about 10 at % to about 50 at %, Nb in a range from about 10 at % to about 20 at %, V in a range between about 10 at % to about 30 at %, and Co in a range between 10 at % to about 40 at %.

10 . The perpendicular magnetic recording medium as recited in claim 1 , wherein a thickness of the first interlayer is in a range between about 2 nm to about 8 nm.

11 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the second interlayer comprises Ru and/or a Ru alloy.

12 . The perpendicular magnetic recording medium as recited in claim 11 , wherein an amount of Ru in the second interlayer is greater than the amount of Ru in the first interlayer.

13 . The perpendicular magnetic recording medium as recited in claim 11 , wherein the second interlayer comprises a Ru alloy including at least one element selected from a group consisting of: Cr, Ta, W, Mo, Nb, V and Co.

14 . The perpendicular magnetic recording medium as recited in claim 1 , wherein a thickness of the second interlayer is in a range between about 4 nm to about 14 nm.

15 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the third interlayer comprises a Ru alloy including an element selected from a group consisting of: Ti in a range between about 20 at % to about 50 at %, Nb in a range between about 20 at % to about 50 at %, Al in a range between about 20 at % to about 40 at %, Ta in a range between about 30 at % to about 50 at %, and Si in a range between about 20 at % to about 40 at %.

16 . The perpendicular magnetic recording medium as recited in claim 15 , wherein the Ru alloy of the third interlayer further comprises an oxide of Ti, Nb, Al and/or Ni, wherein an amount of the oxide in the third interlayer is in a range from greater than 0 vol % to about 40 vol % based on a total volume of the third interlayer.

17 . The perpendicular magnetic recording medium as recited in claim 1 , wherein a thickness of the third interlayer is in a range between about 0.5 nm to about 2 nm.

18 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the magnetic recording layer comprises a plurality of ferromagnetic crystal grains wherein the ferromagnetic crystal grains comprise a CoPt alloy including at least of: Cr, Ti, Ta, Ru, W, Mo, Cu, and B, wherein the ferromagnetic crystal grains are surrounded by at least one oxide of Si, Ti, Ta, B, Cr, W and Nb.

19 . The perpendicular magnetic recording medium as recited in claim 18 , wherein the magnetic recording layer comprises a plurality of layers, wherein a concentration of at least one of Co and Pt in the crystal grains is varied across the plurality of layers.

20 . The perpendicular magnetic recording medium as recited in claim 18 , wherein a non-granular magnetic recording layer is positioned above the magnetic recording layer, the non-granular magnetic recording layer comprising a CoCrPt alloy including at least one element selected from a group consisting of: B, Ta, Ru, Ti, W, Mo and Nb.

21 . The perpendicular magnetic recording medium as recited in claim 1 , wherein the soft magnetic underlayer comprises an amorphous alloy of Co and/or Fe, wherein the amorphous alloy further includes at least one element selected from a group consisting of: Ta, Nb, Zr, B, and Cr, wherein a thickness of the soft magnetic underlayer is in a range between about 10 nm to about 50 nm.

22 . A magnetic data storage system, comprising:

at least one magnetic head;

a perpendicular magnetic recording medium as recited in claim 1 ;

a drive mechanism for passing the magnetic medium over the at least one magnetic head; and

a controller electrically coupled to the at least one magnetic head for controlling operation of the at least one magnetic head.

23 . A method for forming a perpendicular magnetic recording medium, comprising:

providing a substrate;

forming a soft magnetic underlayer above the substrate;

forming a seed layer structure above the soft magnetic underlayer, the seed layer structure comprising a first seed layer and a second seed layer positioned above the first seed layer;

forming an interlayer structure above the seed layer structure, the interlayer structure comprising a first interlayer, a second interlayer positioned above the first interlayer, and a third interlayer positioned above the second interlayer; and

forming a magnetic recording layer above the interlayer structure,

wherein the second seed layer comprises a Ni alloy including at least one oxide,

wherein the first interlayer comprises a Ru alloy,

wherein the second interlayer is formed under a gas pressure that is higher than a gas pressure used to form the first interlayer.

24 . The method as recited in claim 23 , wherein the second interlayer is formed under a gas pressure that is greater than or equal to about 2 Pa, wherein the first interlayer is formed under a gas pressure in a range between about 0.5 Pa to about 1 Pa.

25 . The method as recited in claim 23 , wherein an amount of the oxide in the second seed layer is in a range between about 5 vol % to about 20 vol % based on a total volume of the second seed layer, wherein the first seed layer comprises a Ni alloy that does not include an oxide.