Master carrier for magnetic transfer, inspecting method thereof, and magnetic recording medium producing method
View Patent ↗In a master carrier for magnetic transfer which comprises a support that has a transfer-recording pattern arrayed in the track direction thereof in accordance with the information to be transferred to a magnetic recording medium, and a magnetic layer formed on the transfer-recording pattern of the support, the in-plane distance L (mm) between the hill and the valley of the warped master carrier, the vertical-direction distance H (μm) between the two, and the thickness d (mm) of the master carrier are so defined that they satisfy a relation of 0.05≦H·d 3 /L≦0.6.
1. A process of producing a preformatted magnetic recording medium, which comprises the steps of:
preparing a master carrier for magnetic transfer,
preparing a slave medium comprising a non-magnetic support having a magnetic recording layer thereon,
initially magnetizing said magnetic recording layer of said slave medium to a predetermined direction,
bringing a surface of said master medium into intimate contact with said magnetic recording layer of said slave medium at a predetermined pressure to form a conjoined body, and
applying a transfer magnetic field to said conjoined body in a direction opposite to said predetermined direction, thereby obtaining said magnetic recording medium having said recorded data,
wherein said master carrier comprises a disk surface having a hill and a valley, which result from a warp of said master carrier; said master carrier has an in-plane distance L (mm) between top of the said hill and bottom of the said valley with respect to said disk surface, a vertical-direction distance H (μm) between said hill and said valley with respect to said disk surface, and a thickness d (mm); and said in-plane distance L (mm), said vertical-direction distance H (μm), and said thickness d (mm) satisfy the following formula:
0.05 ≦H·d 3 /L≦ 0.6
2. The process of producing a preformatted magnetic recording medium as claimed in claim 1 , wherein said support to form the transfer-recording pattern comprises a metal.
3. The process of producing a preformatted magnetic recording medium as claimed in claim 1 , wherein said metal comprises at least one of Ni and Al.
4. The process of producing a preformatted magnetic recording medium as claimed in claim 1 , which further comprises a protective film on said support.
5. The process of producing a preformatted magnetic recording medium as claimed in claim 1 , wherein said master carrier further comprises a soft magnetic film on a surface of said master carrier.
6. The process of producing a preformatted magnetic recording medium as claimed in claim 4 , wherein said protective film has a thickness of 3 to 30 nm.
7. The process of producing a preformatted magnetic recording medium as claimed in claim 5 , wherein said soft magnetic film has a thickness of 50 to 500 nm.
8. The process of producing a preformatted magnetic recording medium as claimed in claim 5 , wherein said master carrier further comprises a protective film on said soft magnetic film.