Patent ID: 6753043
Filing Date: 2004-06-22
Classification: B82Y,G11B

Abstract:
A method of making a servo-patterned magnetic recording medium, comprising the sequential steps of:(a) providing a magnetic recording medium, said medium including a magnetic layer having preselected first, higher values of magnetic coercivity Hc and magnetic remanence-thickness product Mrt; (b) providing an apertured mask overlying a surface of said magnetic recording medium, said apertured mask including a plurality of servo pattern openings extending therethrough for selectively exposing a plurality of surface areas of said magnetic recording medium corresponding to said servo pattern; (c) bombarding said apertured mask with ions for implanting said ions into said plurality of exposed surface areas of said magnetic recording medium for selectively reducing said first, higher values of Hc and Mrt of said magnetic layer at said exposed surface areas to preselected second, lower values of Hc and Mrt; wherein: step (a) comprises providing a magnetic recording medium including a magnetic layer having sufficiently high first values of Hc and Mrt such that step (c) provides each of said plurality of exposed, ion-implanted surface areas of said magnetic layer with second, lower values of Hc and Mrt which are sufficiently lower than said first, higher values of Hc and Mrt for functioning as servo pattern-defining areas, but sufficiently high for providing said medium with thermal stability, high amplitude of magnetic transition, and high signal-to-noise ratio, and step (a) comprises providing a magnetic recording medium wherein said preselected first, higher values of Hc and Mrt are in the range from about 6,500 to about 10,000 Oe and in the range from about 0.55 to about 0.60 memu, respectively; and step (c) comprises bombarding said apertured mask to form ion-implanted areas of said magnetic layer having preselected, second, lower values of Hc and Mrt of about 6,000 Oe and about 0.50 memu, respectively; or step (a) comprises providing a magnetic recording medium wherein said preselected first, higher values of Hc and Mrt are about 6,000 Oe and 0.50 memu, respectively; and step (c) comprises forming ion implanted areas having preselected, second, lower values of Hc and Mrt of about 4,000 Oe and 0.40 memu, respectively.