Magnetic recording medium having a patterned soft magnetic layer
A magnetic recording medium includes a non-magnetic substrate; a soft magnetic layer which is formed on the non-magnetic substrate and which includes projected parts arranged on the surface thereof and recessed parts surrounding each of the projected part; and a ferromagnetic layer which is formed on the soft magnetic layer and which includes projected parts and recessed parts reflecting the projected parts and the recessed parts of the soft magnetic layer. Further the magnetic recording medium includes recording areas which have perpendicular magnetic anisotropy and ferromagnetism, and which are formed of the projected parts of the ferromagnetic layer and separated magnetically from their surroundings. A method for manufacture of the magnetic recording medium includes forming a soft magnetic layer including of projected parts arranged regularly on the surface thereof and recessed parts surrounding each projected part; and forming a ferromagnetic layer having perpendicular magnetic anisotropy on the soft magnetic layer.
1. A magnetic recording medium comprising:
a non-magnetic substrate;
a soft magnetic layer formed on the non-magnetic substrate, the soft magnetic layer including a plurality of projected parts arranged regularly on a surface thereof and recessed parts surrounding each of the projected parts;
a ferromagnetic layer formed on the soft magnetic layer, the ferromagnetic layer including projected parts and recessed parts reflecting the projected parts and the recessed parts of the soft magnetic layer; and
recording areas having perpendicular magnetic anisotropy and ferromagnetism, the recording areas being formed of the projected parts of the ferromagnetic layer and being separated magnetically from their surroundings.
2. The magnetic recording medium according to claim 1 , wherein the non-magnetic substrate includes a plurality of projected parts arranged regularly on a surface thereof and recessed parts surrounding each of the projected parts, and the projected parts and recessed parts of the soft magnetic layer reflect the recessed parts and the projected parts of the non-magnetic substrate.
3. The magnetic recording medium according to claim 1 , wherein the non-magnetic substrate has a flat surface, and the soft magnetic layer has the projected parts and the recessed parts on the surface thereof.
4. The magnetic recording medium according to claim 3 , wherein the soft magnetic layer comprises
a soft magnetic film having a flat surface; and
soft magnetic particles arranged regularly separately from each other on the soft magnetic film.
5. The magnetic recording medium according to claim 1 , wherein the soft magnetic layer has such a thickness that a magnetic orientation thereof is stably uniform in an in-plane direction during writing and reading.
6. The magnetic recording medium according to claim 1 , wherein a thickness L 1 of the soft magnetic layer is at least twice a height L 2 of the projected parts of the soft magnetic layer, the thickness and the height being measured along a direction perpendicular to a plane of the substrate.
7. The magnetic recording medium according to claim 1 , wherein a thickness of the ferromagnetic layer is set to be from ½ to ¼ of a height L 2 of the projected parts of the soft magnetic layer, the thickness and the height being measured along a direction perpendicular to a plane of the substrate.
8. The magnetic recording medium according to claim 1 , wherein the ferromagnetic layer is made of an artificial lattice layer.
9. A magnetic recording medium comprising:
a flat non-magnetic substrate;
a ferromagnetic layer formed on the non-magnetic substrate, the ferromagnetic layer including a plurality of projected parts and recessed parts, the projected parts of the ferromagnetic layer serving as recording areas having perpendicular magnetic anisotropy; and
non-recording areas having soft magnetism, buried in the recessed parts of the ferromagnetic layer so as to surround the recording areas.
10. The magnetic recording medium according to claim 9 , wherein the ferromagnetic layer is made of an artificial lattice layer.