Patterned medium, method for fabricating same and method for evaluating same

1. A method for fabricating a patterned medium on which, after forming a magnetic metal thin film as a recording layer by sputtering, magnetic dots arranged in an array are formed by micro-fabricating the magnetic metal thin film, the method comprising:

a dot-forming step for forming a dot array constituted by sample magnetic dots having a predetermined size larger than the magnetic dots targeting a sample medium having a magnetic metal film formed with initial conditions;

a demagnetization step for AC-demagnetizing the dot array;

a ratio measurement step for measuring the ratio of single magnetic domains by observing a magnetic pattern of each of the sample dots after the AC-demagnetization; and

an adjustment step for determining film-forming conditions for forming a solid state magnetic metal thin film by adjusting the film-forming conditions such that the ratio of the single magnetic domains equals to or exceeds a predetermined value.

2. The method for fabricating a patterned medium according to claim 1 , wherein in the dot-forming step, magnetic dots having a single domain particle size determined theoretically from the magnetic metal thin film are formed as the sample magnetic dots.

3. The method for fabricating a patterned medium according to claim 1 , wherein in the adjustment step, when the ratio of the single magnetic domains is less than a predetermined value, the film-forming conditions are adjusted by repeating the dot-forming step, the demagnetization step and the ratio measurement step such that the ratio of the single magnetic domain exceeds the predetermined value after adjusting the film-forming conditions such that the density of the magnetic metal thin film is increased.

4. The method for fabricating a patterned medium according to claim 1 , wherein in the ratio measurement step, the ratio of single magnetic domain is measured by observing a magnetic domain pattern of each AC-demagnetized magnetic dot using a magnetic force microscope.

5. The method for fabricating a patterned medium according to claim 1 , wherein in the adjustment step, a solid state magnetic metal thin film is formed with the film-forming conditions set such that the ratio of single magnetic domain equals to or exceeds approximately 85%.

6. The method for fabricating a patterned medium according to claim 5 , wherein A pressure of a non-volatile gas is 5 mTorr or lower as one of the film-forming condition.

7. The method for fabricating a patterned medium according to claim 6 , wherein in the adjustment step, power supplied during formation of the solid state magnetic metal thin film is 30 W or higher as one of the film-forming conditions.

8. The method for fabricating a patterned medium according to claim 6 , wherein in the adjustment step, a distance between a substrate and a target is 20 cm or less as one of the film-forming conditions.

9. The method for fabricating a patterned medium according to claim 1 , wherein in the adjustment step, the solid state magnetic metal thin film is formed with the film-forming conditions set such that the ratio of the single magnetic domain is approximately 100%.

10. The method for fabricating a patterned medium according to claim 9 , wherein in the adjustment step, a pressure of a non-volatile gas is approximately 3 mTorr as one of the film-forming conditions.

11. The method for fabricating a patterned medium according to claim 10 , wherein in the adjustment step, power supplied during formation of the solid state magnetic metal thin film is 30 W or higher as one of the film-forming conditions.

12. The method for fabricating a patterned medium according to claim 10 , wherein in the adjustment step, a distance between a substrate and a target is 20 cm or less as one of the film-forming conditions.