Magnetic recording medium having patterned auxiliary recording layer and method for manufacturing such magnetic recording medium
View Patent ↗A method for manufacturing a magnetic recording medium for perpendicular magnetic recording includes the steps of forming a first magnetic layer which has magnetic crystal grains exhibiting perpendicular magnetic anisotropy and nonmagnetic substances for magnetically separating the magnetic crystal grains from each other at grain boundaries of the magnetic crystal grains, forming a second magnetic layer which has magnetic grains exchange-coupled to the magnetic crystal grains, a grain boundary width of the magnetic grains being smaller than a grain boundary width of the magnetic crystal grains, and forming separation regions which magnetically separate tracks from each other in regions between the tracks of the magnetic recording medium in at least the second magnetic layer. The separation regions are disposed substantially only in the second magnetic layer of the first magnetic layer and the second magnetic layer.
1. A magnetic recording medium comprising:
a substrate;
a recording layer including an auxiliary recording layer and a main recording layer disposed on said substrate,
wherein the auxiliary recording layer has magnetic portions corresponding to recording bits and separation portions for separating the magnetic portions from each other, and the main recording layer is divided into regions serving as recording bits by a magnetic influence exerted by the auxiliary recording layer,
wherein said main recording layer comprises magnetic crystal grains exhibiting perpendicular magnetic anisotropy and comprising nonmagnetic substances for magnetically separating the magnetic crystal grains from each other at grain boundaries of the magnetic crystal grains,
wherein said auxiliary recording layer has magnetic grains exchange-coupled to the magnetic crystal grains,
wherein a grain boundary width of the magnetic grains are smaller than a grain boundary width of the magnetic crystal grains,
wherein there are separation regions which magnetically separate tracks from each other in regions between the tracks of the magnetic recording medium in at least the auxiliary recording layer, and
wherein the separation regions are disposed substantially only in the auxiliary recording layer of the main recording layer and the auxiliary recording layer.
2. The magnetic recording medium according to claim 1 , wherein a magnetic anisotropy constant Ku of the auxiliary recording layer is larger than a magnetic anisotropy constant Ku of the main recording layer.
3. The magnetic recording medium according to claim 1 , wherein the main recording layer has a granular structure.
4. The magnetic recording medium according to claim 1 , wherein the recording layer is a perpendicular magnetic recording layer.
5. The magnetic recording medium according to claim 1 , wherein magnetic grains are exchange-coupled to the magnetic crystal grains and exchange-coupled to each other with a strength larger than a bonding strength between the magnetic crystal grains in the main recording layer in a direction parallel to a main surface of the substrate.