Patent ID: 7666531
Filing Date: 2010-02-23
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising: a nonmagnetic substrate; a first underlayer formed on the nonmagnetic substrate, and containing, as a main component, at least one element selected from the group consisting, of Ag, Ir, Ni, Pd, Pt, Rh, Hf, Re, Ru, Ti, Ta, Zr, Mg, and Al; a second underlayer formed on and in contact with the first underlayer, and constituted of crystal grains consisting of one of Mg and Al, and a grain boundary region which consists of Si and surrounds the crystal grains; a third underlayer formed on the second underlayer, and containing, as a main component, at least one element selected from the group consisting of Pt, Pd, Ru, Rh, Co, and Ti; and a perpendicular magnetic recording layer formed on the third underlayer.