| 摘要 |
A perpendicular magnetic recording medium is disclosed that achieves improved recordability without deteriorating thermal stability by reducing the switching field. A perpendicular magnetic recording medium of the invention has a first magnetic recording layer and a second magnetic recording layer between with is interposed a coupling layer that ferromagnetically couples the two layers. The first and second magnetic recording layers satisfy an inequality Ku1T1>Ku2T2 in the case where Hk1 >Hk2 and an inequality Ku1T1<Ku2T2 in the case where Hk1<Hk2, where Hk1 and Hk2 are anisotropy magnetic fields, Ku1 and Ku2 are uniaxial anisotropy constants, and T1 and T2 are thicknesses of the first magnetic recording layer and the second recording layer, respectively. An exchange coupling energy between the magnetic recording layers is preferably at least 5×10−3 erg/cm2. Advantageously, the coupling layer is mainly composed of a material selected from V, Cr, Fe, Co, Ni, Cu, Nb, Mo, Ru, Rh, Ta, W, Re, and Ir, and has a thickness of at most 2 nm. At least one of the magnetic recording layers preferably has a granular structure. |
