Patent ID: 7510788
Filing Date: 2009-03-31
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising a magnetic film formed on a nonmagnetic substrate, wherein the magnetic film is multilayered and comprises alternately laminated first magnetic layers of cobalt containing no additive and second layers of palladium, the second layers containing silicon oxide, wherein crystalline magnetic anisotropy energy of the magnetic trim is approximated by E≈Ku 1 sin 2 θ+Ku 2 sin 4 θ, where Ku 1 and Ku 2 are uniaxial anisotropy constants, θ is an angle between spontaneous magnetization and an axis of easy magnetization of the magnetic film, and a crystalline magnetic anisotropy constant Ku, where Ku=Ku 1 +Ku 2 , and the Ku and the Ku 2 obtained by magnetic anisotropy measurement using a torque magnetization meter under a condition of approximately saturated magnetization of the magnetic film satisfies Ku 2 /Ku≧0.25.