Magnetic transfer method and apparatus
A favorable magnetic transfer is, performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.
1 - 17 . (canceled)
18 . A magnetic transfer method comprising the steps of:
forming a pattern for transferring data on a magnetic layer of a master medium;
subjecting a magnetic layer of a slave medium to an initial magnetization process comprising applying an initial direct current magnetic field to said magnetic layer of said slave medium unidirectionally in a direction perpendicular to a track direction to initially magnetize said magnetic layer of said slave medium;
conjoining said magnetic layer with a magnetic layer of a slave medium to form a conjoined body;
applying a transfer magnetic field to the respective magnetic layers of the conjoined body to magnetically transfer the data to the magnetic layer of the slave medium, wherein said transfer magnetic field is applied to the respective magnetic layers in a direction opposite that in which the initial direct current magnetization has been performed, and
wherein the transfer magnetic field is applied in a width larger than that of a track of said slave medium having the largest radius.
19 . A magnetic transfer method as defined in claim 18 , wherein the initial magnetization process and the application of the transfer magnetic field are performed by the same device.
20 . A magnetic transfer method as defined in claim 18 , wherein the conjoined body is moved relative to the transfer magnetic field so as to pass the entirety of a track surface of said slave medium through said transfer magnetic field.
21 . A magnetic transfer method as defined in claim 18 , wherein the initial magnetization process of said slave medium is performed after said slave medium is conjoined with said master medium.
22 . A magnetic transfer method as defined in claim 18 , wherein said pattern formed on said master medium is a negative pattern.
23 . A magnetic transfer method as defined in claim 18 , wherein the magnetic transfer master medium comprises a substrate provided with a surface on which an uneven pattern corresponding to the data has been formed.
24 . A magnetic transfer method as defined in claim 18 , wherein depressions on a surface of said master medium are filled with the magnetic layer of said master medium.
25 . A magnetic transfer method as defined in claim 18 , wherein a non-magnetic sub-layer is formed below said magnetic layer of said slave medium.
26 . A magnetic transfer method as defined in claim 18 , wherein a thickness of the magnetic recording layer of said slave medium is formed in the range of 10 to 500 nm.
27 . A magnetic transfer method as defined in claim 18 , wherein a thickness of the magnetic recording layer of said slave medium is formed in the range of 20 to 200 nm.
28 . A magnetic transfer method as defined in claim 18 , wherein an intensity of the transfer magnetic field is greater than or equal to 0.5 times and less than or equal to 3.5 times a coercive force of the magnetic layer of the slave medium.
29 . A magnetic transfer method as defined in claim 18 , further comprising moving the conjoined body relative to said transfer magnetic field so as to pass the entirety of a track surface of said slave medium through the transfer magnetic field.
30 . A magnetic transfer method as defined in claim 18 , wherein said magnetic transfer field is applied by an electromagnetic apparatus.
31 . A magnetic transfer method as defined in claim 18 , wherein said magnetic transfer field is applied by a permanent magnet apparatus.
32 . A magnetic transfer method as defined in claim 18 , wherein the initial magnetization process of said slave medium is performed before said slave medium is conjoined with said master medium.
33 . A magnetic transfer method comprising the steps of:
forming a pattern for transferring data on a magnetic layer of a master medium;
subjecting a magnetic layer of a slave medium to an initial magnetization process comprising applying an initial direct current magnetic field to said magnetic layer of said slave medium unidirectionally in a direction perpendicular to a track direction to initially magnetize said magnetic layer of said slave medium;
conjoining said magnetic layer with a magnetic layer of a slave medium to form a conjoined body;
applying a transfer magnetic field to the respective magnetic layers of the conjoined body to magnetically transfer the data to the magnetic layer of the slave medium, wherein said transfer magnetic field is applied to the respective magnetic layers in a direction opposite that in which the initial direct current magnetization has been performed, and
wherein the transfer magnetic field and initial direct current magnetic field are applied by the same magnetization device.
34 . A magnetic transfer method as defined in claim 33 , wherein the initial magnetization process of said slave medium is performed after said slave medium is conjoined with said master medium.