Patent ID: 7892663
Filing Date: 2011-02-22
Classification: G11B

Abstract:
1. A perpendicular magnetic recording medium comprising: an underlayer provided over a substrate; a magnetic layer formed over said underlayer, in which magnetic grains comprising Co, Cr, and Pt with columnar structure and oxides are contained; and a ferromagnetic-metal layer which is formed over said magnetic layer and which does not contain an oxide, wherein said magnetic layer comprises at least two layers including a first magnetic layer formed at an underlayer side of the magnetic layer and a second magnetic layer formed at a ferromagnetic-metal layer side of the magnetic layer, in which grain boundaries of said first magnetic layer include a Cr oxide and at least one oxide selected from Si, Ti, Nb, and Ta, and grain boundaries of said second magnetic layer include at least one oxide selected from Si, Ti, Nb, and Ta where the sum of element concentrations of Cr and oxygen in any Cr oxide in the second magnetic layer is smaller than that in said first magnetic layer and is greater than 0 at % and less than 5 at %.