A perpendicular magnetic recording medium adapted for high recording density and high data recording rate comprises a non-magnetic substrate having at least one surface with a layer stack formed thereon, the layer stack including a perpendicular recording layer containing a plurality of columnar-shaped magnetic grains extending perpendicularly to the substrate surface for a length, with a first end distal the surface and a second end proximal the surface, wherein each of the magnetic grains has: (1) a gradient of perpendicular magnetic coercivity H.sub.k extending along its length between the first end and second ends; and (2) predetermined local exchange coupling strengths along the length.

According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium, a recording unit and a reproducing unit. The magnetic recording medium includes a first track and a second track, the first track extending in a first direction, the second track extending in the first direction and being arranged with the first track in a second direction intersecting the first direction. The first track includes first and second sub-tracks extending in the first direction. The second track includes third and fourth sub-tracks extending in the first direction. The second sub-track is disposed between the first and fourth sub-tracks. The third sub-track is disposed between the second and fourth sub-tracks. The recording unit records information in the first and second tracks. The reproducing unit reproduces first information recorded in the first track. The reproducing unit reproduces second information recorded in the second track.

A magnetic disk device according to an embodiment includes: a magnetic disk including a plurality of tracks; a magnetic head that performs data reading and data writing on the magnetic disk; a plurality of servo regions that is provided in each of the plurality of tracks, and at least partially includes a first physical pattern, the first physical pattern being a physical pattern after writing of a first data pattern including position information of each of the plurality of tracks; and a controller that controls the magnetic head, wherein the plurality of servo regions includes one of a first servo region including the first physical pattern, and a second servo region including a second physical pattern, the second physical pattern being a physical pattern after writing of a second data pattern different from the first data pattern, for each of the plurality of tracks, and the controller performs determination as to which of the first and second physical patterns a third servo region has, the third servo region being one of a servo region among the plurality of servo regions included in the plurality of tracks.