Perpendicular magnetic recording medium with grain boundary controlling layers

摘要

In one embodiment, a perpendicular magnetic recording medium includes an oxide recording layer including an oxide and a non-oxide recording layer which does not contain an oxide positioned above the oxide recording layer. The oxide recording layer includes a region R1 where a grain boundary width in a direction parallel to a plane of formation of R1 increases therealong from a lowermost portion of the oxide recording layer toward a medium surface, a region R3 positioned above R1 wherein a grain boundary width increases therealong toward the medium surface, a region R2 where a grain boundary width of R2 decreases therealong from R1 to R3, with R2 being positioned between R1 and R3, and a region R4 where a grain boundary width of R4 decreases therealong from R3 toward the medium surface, with R4 being positioned above R3 and near an uppermost portion of the oxide recording layer.

主权项

1. A perpendicular magnetic recording medium, comprising:
an oxide recording layer comprising an oxide; and a non-oxide recording layer which does not contain an oxide positioned above the oxide recording layer, wherein the oxide recording layer comprises:
a region R1 where a grain boundary width in a direction parallel to a plane of formation of the region R1 increases therealong from a lowermost portion of the oxide recording layer toward a medium surface;at least one region R3 positioned above the region R1, and wherein a grain boundary width increases therealong toward the medium surface;at least one region R2 where a grain boundary width of the region R2 decreases therealong from the region R1 to the region R3, the at least one region R2 being positioned between the region R1 and the region R3; andat least one region R4 where a grain boundary width of the region R4 decreases therealong from the region R3 toward the medium surface, the at least one region R4 being positioned above the region R3 and near an uppermost portion of the oxide recording layer,wherein a magnetic grain in the region R4 is physically characterized by growth directly on a magnetic grain in the region R3, the magnetic grain in the region R3 being physically characterized by growth directly on a magnetic grain in the region R2, the magnetic grain in the region R2 being physically characterized by growth directly on the a magnetic grain in the region R1.