Patent ID: 8025993

Claim:
A medium, comprising: a non-magnetic substrate having a substrate surface; and a layer stack formed over said substrate surface, said layer stack including; a magnetically soft underlayer; an interlayer structure above said magnetically soft underlayer; and at least one magnetic recording layer above said interlayer structure; wherein said interlayer structure includes: a first interlayer of a first non-magnetic material proximal said magnetically soft underlayer, said first non-magnetic material containing Ru, wherein said first interlayer includes a first thickness, and wherein said first non-magnetic material is of general formula RuX, where X is at least one element selected from the group consisting of: Mo, Ni, W, Zr, and Re; a second interlayer of a second non-magnetic material above said first interlayer, said second non-magnetic material not containing Ru, wherein said second interlayer includes a second thickness; and a third interlayer of a third non-magnetic material above said second interlayer, said third non-magnetic material containing Ru, wherein said third interlayer includes a third thickness.