Magnetic recording medium and manufacturing method therefor
The present invention provides a novel discrete track medium having a high magnetic recording density and manufacturing method therefor. This magnetic recording medium is a disk-shaped magnetic recording medium comprising a soft magnetic layer, a magnetic layer thereover, and an intermediate layer directly under the magnetic recording layer, wherein the magnetic recording layer comprises a plurality of magnetic recording tracks arranged in the radial direction of the magnetic recording medium, and each magnetic recording track is separated from the other in the radial direction of the disk by concave sections and convex sections formed alternately on the upper surface of the intermediate layer in the radial direction of the disk.
1 . A magnetic recording medium in a shape of a disk, comprising:
a soft magnetic layer;
a magnetic recording layer over the soft magnetic layer; and
an intermediate layer directly under said magnetic recording layer, wherein
said magnetic recording layer comprises a plurality of magnetic recording tracks arranged in the radial direction of the magnetic recording medium, and
each magnetic recording track is separated from the other in the radial direction of said disk by concave sections and convex sections formed alternately on the upper surface of said intermediate layer in the radial direction of said disk.
2 . The magnetic recording medium according to claim 1 , further comprising a portion where said magnetic recording tracks are separated also in the circumferential direction of said disk by the concave sections and convex sections formed on the upper surface of said intermediate layer in the circumferential direction of said disk.
3 . The magnetic recording medium according to claim 1 , wherein said convex sections are made of carbon.
4 . The magnetic recording medium according to claim 1 , wherein the average particle size of magnetic particles used for said magnetic recording layer is in a 2-15 nm range.
5 . The magnetic recording medium according to claim 4 , wherein the surfaces of said magnetic particles are surface-treated so that the minute particles attract each other in a self-assembling way.
6 . The magnetic recording medium according to claim 4 , wherein said magnetic particles are FePt nano-particles.
7 . The magnetic recording medium according to claim 1 , wherein said intermediate layer is formed of one or more layers of non-magnetic material.
8 . A method for manufacturing a magnetic recording medium in a shape of a disk comprising a soft magnetic layer, a magnetic recording layer over the soft magnetic layer, and an intermediate layer directly under said magnetic recording layer, the method comprising:
forming concave sections and convex sections alternately on the upper surface of said intermediate layer in the radial direction of said disk; and
filling magnetic particles into said concave sections in a self-assembling way.
9 . The method for manufacturing a magnetic recording medium according to claim 8 , further comprising forming concave sections and convex sections on the upper surface of said intermediate layer in the circumferential direction of said disk.
10 . The method for manufacturing a magnetic recording medium according to claim 8 , further comprising treating the upper surfaces of the convex sections to be hydrophilic or hydrophobic so as to repel the magnetic particles.
11 . The method for manufacturing a magnetic recording medium according to claim 10 , wherein
the upper surfaces of said convex sections are treated to be hydrophilic, and
when said magnetic particles are filled into said concave sections, said magnetic particles are surrounded by a dispersion stabilizing agent, and hydrophobic groups of the dispersion stabilizing agent are facing the outside.
12 . The method for manufacturing a magnetic recording medium according to claim 8 , further comprising:
forming a layer made of carbon on at least the uppermost part of the intermediate layer;
forming a resist pattern on said carbon layer;
forming concave sections on the upper surface of said intermediate layer by etching said carbon layer; and
then, forming convex sections on the upper surface of said intermediate layer by partially removing said resist pattern.
13 . The method for manufacturing a magnetic recording medium according to claim 8 , wherein the average particle size of said magnetic particles is in a 2-15 nm range.
14 . The method for manufacturing a magnetic recording medium according to claim 8 , wherein the surfaces of the magnetic particles are surface-treated so that the minute particles attract each other in a self-assembling way.
15 . The method for manufacturing a magnetic recording medium according to claim 14 , wherein said magnetic particles are FePt nano-particles.
16 . The method for manufacturing a magnetic recording medium according to any of claim 8 , wherein said intermediate layer is formed of one or more layers of non-magnetic material.