Patent ID: 7651795

Claim:
A perpendicular magnetic recording medium, comprising: a substrate; a soft-magnetic underlayer deposited on said substrate; a lower intermediate layer containing Ru deposited on said soft-magnetic underlayer; an upper intermediate layer deposited on said lower intermediate layer and having Ru crystal grains and oxide crystal grain boundaries; a magnetic recording layer deposited on said upper intermediate layer and having crystal grains and oxide crystal grain boundaries, wherein the crystal grains of said magnetic recording layer grow epitaxially on the Ru crystal grains of said upper intermediate layer, and the crystal grain boundaries of said magnetic recording layer grow on the crystal grain boundaries of said upper intermediate layer, wherein said magnetic recording layer consists of a CoCrPt-based alloy to which is added at least one selected from the group consisting of Si oxide, Al oxide, Ti oxide, Cr oxide and Mg oxide, and wherein a difference in position in the depth direction, at which the contents of oxygen and Co maintain 95% of the value of respective contents thereof at the mid position in the depth direction of said magnetic recording layer, is 1 nm or less in a depth profile of the element content around the interface of said magnetic recording layer with said upper intermediate layer obtained by making discharge of an oxide target faster than that of a magnetic target during formation of said magnetic layer.