Method of initializing perpendicular magnetic recording medium, perpendicular magnetic recording medium and magnetic recording apparatus

Abstract

The present invention provides a method of initializing a perpendicular magnetic recording medium in which a magnetic field having a magnetic field strength Hex is applied to a perpendicular magnetic recording medium having a magnetic layer having a coercive force Hc to initialize the magnetic layer, the method comprising the steps of: controlling a magnetic field strength HexP in a direction parallel to the medium surface of the magnetic field so that HexP>1.3×Hc; and controlling a magnetic field strength HexV in a direction perpendicular to the medium surface of the magnetic field so that HexV

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an essential portion of a slave disk;

FIG. 2 is a perspective view of an essential portion of a demagnetization device;

FIG. 3 is a plan view showing a method of applying a magnetic field for demagnetization;

FIG. 4 is a diagram schematically showing the direction of a demagnetizing magnetic field applied to a magnetic recording layer;

FIG. 5 is a plan view of a master disk;

FIG. 6 is an enlarged perspective view of a portion of the master disk showing a fine projection-recess pattern in the surface;

FIGS. 7A to 7E are sectional views of a substrate for explaining the flow of processing for forming a magnetic layer;

FIG. 8 is a perspective view of an essential portion of a magnetic transfer device;

FIGS. 9A to 9C are sectional views for explaining a basic process for magnetic transfer;

FIG. 10 is a graph showing the results of an example of the present invention; and

FIG. 11 is a graph showing the results of an example of the present invention.

Claims

1. A method of initializing a perpendicular magnetic recording medium in which a magnetic field having a magnetic field strength Hex is applied to a perpendicular magnetic recording medium having a magnetic layer having a coercive force Hc to initialize the magnetic layer, the method comprising the step of controlling a magnetic field strength HexP in a direction parallel to the medium surface of the magnetic field so that HexP>1.3×Hc.

2. A method of initializing a perpendicular magnetic recording medium in which a magnetic field having a magnetic field strength Hex is applied to a perpendicular magnetic recording medium having a magnetic layer having a coercive force Hc to initialize the magnetic layer, the method comprising the step of controlling a magnetic field strength HexV in a direction perpendicular to the medium surface of the magnetic field so that HexV<Hc.

3. A method of initializing a perpendicular magnetic recording medium in which a magnetic field having a magnetic field strength Hex is applied to a perpendicular magnetic recording medium having a magnetic layer having a coercive force Hc to initialize the magnetic layer, the method comprising the steps of: controlling a magnetic field strength HexP in a direction parallel to the medium surface of the magnetic field so that HexP>1.3×Hc; andcontrolling a magnetic field strength HexV in a direction perpendicular to the medium surface of the magnetic field so that HexV<Hc.

4. The method of initializing a perpendicular magnetic recording medium according to claim 1, wherein a magnetic field generation device is provided and the perpendicular magnetic recording medium is alternating-current-demagnetized along a circumferential direction of the perpendicular magnetic recording medium by applying a magnetic field along the circumferential direction while moving the perpendicular magnetic recording medium relative to the magnetic field generation device.

5. The method of initializing a perpendicular magnetic recording medium according to claim 2, wherein a magnetic field generation device is provided and the perpendicular magnetic recording medium is alternating-current-demagnetized along a circumferential direction of the perpendicular magnetic recording medium by applying a magnetic field along the circumferential direction while moving the perpendicular magnetic recording medium relative to the magnetic field generation device.

6. The method of initializing a perpendicular magnetic recording medium according to claim 3, wherein a magnetic field generation device is provided and the perpendicular magnetic recording medium is alternating-current-demagnetized along a circumferential direction of the perpendicular magnetic recording medium by applying a magnetic field along the circumferential direction while moving the perpendicular magnetic recording medium relative to the magnetic field generation device.

7. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 1, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

8. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 2, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

9. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 3, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

10. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 4, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

11. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 5, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

12. A perpendicular magnetic recording medium initialized by the method of initializing a perpendicular magnetic recording medium according to claim 6, wherein the perpendicular magnetic recording medium undergoes magnetic transfer of a magnetic pattern formed of an array of magnetic layer portions on a surface of a perpendicular magnetic transfer master disk, which is a disk-like substrate, according to information to be transferred to the perpendicular magnetic recording medium by applying a transfer magnetic field while the perpendicular magnetic transfer master disk is being maintained in close contact with the perpendicular magnetic recording medium.

13. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 7

14. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 8.

15. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 9.

16. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 10.

17. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 11.

18. A magnetic recording apparatus comprising the perpendicular magnetic recording medium according to claim 12.