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Abstract

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 Ku₁T₁2T₂ in the case where Hk₁2, 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.

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First Claim