Patent ID: 9697858
Date: 2017-07-04
CPC Classifications: G11B

Claim:
1. A perpendicular magnetic recording medium comprising: a non-magnetic substrate, an underlayer comprising an alloy made from a magnetic metal selected from the group consisting of Co, Fe, and Ni, and an element having high amorphous structure organization potency selected from the group consisting of Zr, Ta, Nb, Ti, Mo, W, Si and B, a lower orientation control layer, arranged directly on the underlayer, made of Ru or Ru alloy, and having an hcp structure, an upper orientation control layer, arranged directly on the lower orientation control layer, made of an alloy that contains one element selected from the group consisting of Co and Ni and an element selected from the group consisting of W and Mo, and having an fcc or hcp structure, an intermediate layer, arranged directly on the upper orientation control layer, made of non-alloyed Ru and having a thickness of 8 nm to 20 nm, and a magnetic recording layer arranged directly on the intermediate layer, wherein the layers are stacked sequentially on the non-magnetic substrate and wherein the underlayer has either (i) an amorphous single-layer structure or (ii) a stacking structure configured by a plurality of layers in which at least a layer that is in contact with the lower orientation control layer on the non-magnetic substrate side is amorphous.