Recording medium and method of forming the same

1. A recording medium comprising:

a servo layer configured to have a nucleation field value, wherein the servo layer is a magnetic layer;

a data recording layer configured to have a saturation field value, wherein the nucleation field value of the servo layer is greater than or equal to 80% of the saturation field value of the data recording layer, and wherein the data recording layer is a magnetic layer;

a first intermediate layer disposed on the servo layer, wherein the data recording layer is disposed on the first intermediate layer;

a second intermediate layer, wherein the servo layer is disposed on the second intermediate layer;

a crystalline underlayer comprising a first side and a second side, wherein the second side opposes the first side, and wherein the second intermediate layer is disposed on the first side of the crystalline underlayer; and

an amorphous underlayer disposed on the second side of the crystalline underlayer, wherein the crystalline underlayer or the amorphous underlayer is a magnetic layer.

2. The recording medium according to claim 1 , further comprising a substrate,

wherein the amorphous underlayer is disposed between the substrate and the crystalline underlayer.

3. The recording medium according to claim 1 , further comprising a substrate,

wherein the crystalline underlayer is disposed between the substrate and the servo layer.

4. The recording medium according to claim 1 , wherein the servo layer is configured to provide a servo pattern information.

5. The recording medium according to claim 1 , wherein the data recording layer is configured to record data.

6. The recording medium according to claim 1 , wherein the servo layer is configured to have a coercivity value greater than 10 kOe.

7. The recording medium according to claim 1 , wherein the nucleation field value of the servo layer is greater than 7.0 kOe.

8. A system comprising:

a head; and

the recording medium according to claim 1 ,

wherein

the head writes data to the servo layer, and

the servo layer has a saturation field value less than or equal to 80% of a maximum writing field value of the head.

9. The recording medium according to claim 1 , further comprising an overcoat layer,

wherein the data recording layer is disposed between the overcoat layer and the servo layer.

10. The recording medium according to claim 9 , wherein the overcoat layer comprises diamond like carbon (DLC).

11. The recording medium according to claim 1 , wherein:

the servo layer comprises a cap layer; and

the cap layer reduces a saturation field applied to the servo layer.

12. The recording medium of claim 1 , wherein:

the first intermediate layer is in contact with the servo layer;

the data recording layer is in contact with the first intermediate layer;

the servo layer is in contact with the second intermediate layer;

the second intermediate layer is in contact with the first side of the crystalline underlayer; and

the amorphous underlayer is in contact with the second side of the crystalline underlayer.

13. The recording medium of claim 1 , wherein the crystalline underlayer and the amorphous underlayer are magnetic layers.

14. A system comprising:

a head; and

the recording medium of claim 1 ,

wherein

a change in a resultant magnetization field of the servo layer divided by a change in a magnetic field applied to the servo layer is equal to a first ratio multiplied by a reciprocal of one minus a second ratio,

the first ratio is equal to a remnant magnetization field of the servo layer when the applied magnetic field is reduced to zero, and

the second ratio is an indicator of a slope of a hysteresis loop of the servo layer.

15. A system comprising:

a head; and

the recording medium of claim 1 ,

wherein

a change in a resultant magnetization field of the data recording layer divided by a change in a magnetic field applied to the data recording layer is equal to a first ratio multiplied by a reciprocal of one minus a second ratio,

the first ratio is equal to a remnant magnetization field of the data recording layer when the applied magnetic field is reduced to zero, and

the second ratio is an indicator of a slope of a hysteresis loop of the data recording layer.

16. A method of forming a recording medium, the method comprising:

providing an amorphous underlayer layer;

applying a crystalline underlayer on the amorphous underlayer, wherein the crystalline underlayer or the amorphous underlayer is a magnetic layer;

applying a first intermediate layer on the crystalline underlayer;

applying a servo layer on the first intermediate layer, wherein the servo layer is a magnetic layer and is configured to have a nucleation field value;

applying a second intermediate layer on the servo layer; and

applying a data recording layer on the second intermediate layer, wherein the data recording layer is a magnetic layer and is configured to have a saturation field value, and wherein the nucleation field value of the servo layer is greater than or equal to 80% of the saturation field value of the data recording layer.

17. The method according to claim 16 , further comprising providing a substrate,

wherein the amorphous underlayer is disposed between the substrate and the crystalline underlayer.