Patent ID: 8119263

Claim:
A magnetic recording medium comprising: a substrate, and a perpendicular recording layer on the substrate, wherein the recording layer comprises: a first magnetic layer closest to the substrate and comprising a Co-containing alloy, wherein the first magnetic layer comprises magnetic grains separated by grain boundaries of non-ferromagnetic material, wherein the non-ferromagnetic material comprises an oxide; and a second magnetic layer comprising a CoCr-containing alloy, wherein the second magnetic layer comprises magnetic grains separated by grain boundaries, and wherein the grain boundaries in the second magnetic layer comprise substantially no non- ferromagnetic material, such that the exchange coupling in the second magnetic layer is stronger than the exchange coupling in the first magnetic layer, and wherein the first magnetic layer and the second magnetic layer are in direct physical contact and Hc-Hn of the recording layer is between about 2000 Oe and about 4000 Oe.