Magnetic recording medium
A magnetic recording medium includes, in a main surface of a glass substrate on which a magnetic recording layer is formed, a plurality of annular first thermally-conductive regions having a larger thermal conductivity than the glass substrate that are provided concentrically with the glass substrate. The first thermally-conductive regions are each provided so that it extends across a plurality of tracks. The first thermally-conductive region has a radial width larger than a depth, from the main surface, of the first thermally-conductive region.
1. A magnetic recording medium used for heat-assisted recording, comprising:
a glass substrate having a shape of an annular disk; and
a magnetic recording layer provided on at least one of two main surfaces of said glass substrate and including a plurality of annular tracks arranged in a radial direction, each of said plurality of annular tracks having a plurality of sectors into which each track of said plurality of annular tracks are divided in a circumferential direction to provide recording regions,
a plurality of annular first thermally-conductive regions having a larger thermal conductivity than said glass substrate, provided concentrically with said glass substrate and arranged at said main surface of said glass substrate on which said magnetic recording layer is formed, each annular first thermally-conductive region of said plurality of annular first thermally-conductive regions being provided so that said first thermally-conductive region extends across a plurality of said annular tracks, and each annular first thermally-conductive region of said plurality of annular first thermally-conductive regions having a radial width larger than a depth, from said main surface, of said annular first thermally-conductive region.
2. The magnetic recording medium according to claim 1 , wherein said depth, from said main surface, of said annular first thermally-conductive region is not less than 5 nm and less than 20 nm.
3. The magnetic recording medium according to claim 1 , wherein an area of each of said plurality of annular first thermally-conductive regions disposed per unit area of said glass substrate increases as said area of each of said plurality of said first annular thermally-conductive regions is located proximate to an inner circumferential periphery of said glass substrate.
4. The magnetic recording medium according to claim 1 , further comprising:
a second thermally-conductive region extending in the radial direction of said glass substrate so that said second thermally-conductive region crosses each of said plurality of annular first thermally-conductive regions;
wherein said second thermally-conductive region has a larger thermal conductivity than said glass substrate.
5. The magnetic recording medium according to claim 4 , wherein a depth, from said main surface, of said second thermally-conductive region is not less than 5 nm and less than 20 nm.
6. The magnetic recording medium according to claim 4 , wherein an area of said second thermally-conductive region disposed per unit area of said glass substrate increases as said area of said second thermally-conductive region is located proximate to an inner circumferential periphery of said glass substrate.