A corrosion resistant perpendicular magnetic recording medium comprises:
(a) a non-magnetic substrate having a surface; and (b) a layer stack
formed over the substrate surface and comprising, in overlying sequence
from the surface: (i) a magnetically soft underlayer (SUL); (ii) at least
one non-magnetic interlayer; and (iii) at least one magnetically hard
perpendicular recording layer; wherein the SUL comprises an FeCo-based
alloy material having a composition selected to provide: (1) a
substantially amorphous microstructure with a smooth surface in contact
with the non-magnetic interlayer; (2) high saturation magnetization Ms
greater than about 1.6 T; and (3) corrosion resistance.