Patent ID: 8871367
Filing Date: 2014-10-28
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising: a non-magnetic substrate; a homogeneous soft-magnetic underlayer; a non-magnetic underlayer; a homogeneous ferromagnetic intermediate layer; a non-magnetic intermediate layer; a perpendicular magnetic recording layer, wherein the soft-magnetic underlayer, the non-magnetic underlayer, the ferromagnetic intermediate layer, the non-magnetic intermediate layer, and the perpendicular magnetic recording layer are sequentially stacked on the non-magnetic substrate, with the soft-magnetic underlayer contacting the non-magnetic substrate, the non-magnetic underlayer contacting the soft-magnetic underlayer, the ferromagnetic intermediate layer contacting the non-magnetic underlayer, the non-magnetic intermediate layer contacting the ferromagnetic intermediate layer, and the perpendicular magnetic recording layer contacting the non-magnetic intermediate layer, and wherein the ferromagnetic intermediate layer is formed of a CoCr-based alloy, a product (Bs·t) of a saturation magnetic flux density and film thickness of the ferromagnetic intermediate layer is within a range of 0.15 to 3.6 T·nm, and the non-magnetic intermediate layer has a film thickness of 3 nanometers or more.