Patent ID: 7208236

Claim:
A magnetic recording medium which is mounted to a hard disk drive in a Load Unload (LUL) system and in which information is recorded by the use of a magnetic recording head of on a Negative Pressure Air Bearing (NPAB) slider so that said magnetic recording head can have a flying height not greater than 15 nm, said magnetic recording medium comprising: a substrate; a magnetic layer formed on said substrate; a carbon-based protection layer formed on said magnetic layer; and a lubrication layer formed on said carbon-based protection layer; said carbon-based protection layer comprising a rear boundary portion facing said magnetic layer and a front boundary portion facing said lubrication layer, said rear boundary portion comprising carbon and hydrogen, said front boundary portion including no hydrogen but comprising carbon and nitrogen so that concentration of nitrogen with respect to carbon falls within a range not smaller than 4 at % and not greater than 10 at %.