Patent ID: 9093100
Filing Date: 2015-07-28
Classification: G11B

Abstract:
1. A magnetic recording medium comprising: a non-magnetic substrate; a magnetic recording layer of a granular structure, where pillar-shaped magnetic particles spatially have nonmagnetic boundary portions therebetween, on the nonmagnetic substrate; and an exchange coupling layer provided on the magnetic recording layer to add an action of exchange coupling the magnetic particles, wherein reversed magnetic domain nucleation magnetic field Hn is −2000 Oe or more, a ratio Hn/Hc of reversed magnetic domain nucleation magnetic field Hn to coercive force Hc is −0.5 or less, and a film thickness of the exchange coupling layer is 7 nm or less, wherein said exchange coupling layer has been subject to ion irradiation and an amount of change in a ratio c/a of a c-axis to an a-axis in a crystal lattice of a metal having a hexagonal close-packed structure contained in the exchange coupling layer is 10.21% or more after performing said ion irradiation.