Patent ID: 7112376

Claim:
A magnetic recording medium comprising: a nonmagnetic polymer support having a thickness of from 10 to 200 μm, said polymer support being a resin film containing at least one of aromatic polyimide, aromatic polyamide, aromatic polyamideimide, polyether ketone, polyether sulfone, polyether imide, polysulfone, polyphenylene sulfide, polyethylene naphthalate, polyethylene terephthalate, polycarbonate, triacetate cellulose, and a fluorine resin; a subbing layer which contains at least one of a polyimide resin, a polyamideimide resin, a silicone resin and a fluorine resin and has, at its surface, protrusions having a height of from 5 to 60 nm; a first under layer which is constituted by a nonmetal element, per se, a compound consisting of nonmetal elements, or a compound containing titanium and a nonmetal element; a second under layer containing at least one element selected from the group consisting of chromium, titanium, iridium, platinum, palladium, ruthenium, rhodium, rhenium, osmium, cobalt, tungsten, vanadium, iron and molybdenum; and a magnetic layer which contains a ferromagnetic metal alloy containing at least cobalt, platinum and chromium, and a nonmagnetic compound, in this order.