Patent ID: 6846577

Claim:
A magnetic recording medium comprising: a substrate; a ferromagnetic layer; and a single nonmagnetic under-layer formed between said substrate and said ferromagnetic layer, said ferromagnetic layer being formed on said nonmagnetic under-layer; wherein the coercivity of the magnetic recording medium is not less than 2000 Oe; wherein a fluctuation field of magnetic viscosity at a field strength equal to remanence coercivity or coercivity is not less than 30 Oe; wherein said nonmagnetic under-layer comprises one of Cr and a Cr-alloy wherein the Cr-alloy is an alloy of Cr and at least one element selected from the group consisting of V, W, Ti, Si and Mo; and wherein a thickness of said under-layer is from 3 nm to 50 nm.