Magnetic recording medium with multi-portion carbon-based protection layer, and apparatus thereof
View Patent ↗In a magnetic recording medium which comprises a substrate ( 1 ), a magnetic layer ( 3 ) formed on the substrate, a carbon-based protection layer ( 4 ) comprising carbon and formed on the magnetic layer, and a lubrication layer ( 5 ) formed on the carbon-based protection layer, the carbon-based protection layer comprises a hydrogenated carbon protection layer ( 4 a ) facing the magnetic layer and a nitrogenated carbon protection layer ( 4 b ) facing the lubrication layer. The hydrogenated carbon protection layer ( 4 a ) comprises carbon and hydrogen. The nitrogenated carbon protection layer ( 4 b ) includes no hydrogen but comprises carbon and nitrogen.
1. 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 %.
2. 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,
wherein a hydrogenated carbon protection layer facing said magnetic layer comprises said rear boundary portion and a nitrogenated carbon protection layer facing said lubrication layer comprises said front boundary portion, said hydrogenated carbon protection layer comprising carbon and hydrogen, said nitrogenated carbon protection layer 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 %.
3. A magnetic recording medium as claimed in claim 1 or 2 , wherein said lubricant layer comprises a lubricant having, as a terminal group, a hydroxyl group (OH − ) or a carboxyl group (COOH − ).
4. A magnetic recording medium as claimed in claim 1 or 2 , wherein said magnetic recording medium has a principal surface having a surface roughness Ra of 0.7 nm or less.
5. A magnetic recording medium as claimed in claim 1 or 2 , wherein said lubrication layer has a thickness smaller than 18 angstroms.
6. A hard disk drive comprising a magnetic recording medium which is mounted to a the hard disk drive in a Load Unload (LUL) system and in which information is recorded by the use of a magnetic recording head of 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 comprising carbon and 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 %.
7. A hard disk drive as claimed in claim 6 , wherein said lubricant layer comprises a lubricant having, as a terminal group, a hydroxyl group (OH − ) or a carboxyl group (COOH − ).
8. A hard disk drive as claimed in claim 6 , wherein said magnetic recording medium has a principal surface having a surface roughness Ra of 0.7 nm or less.
9. A hard disk drive as claimed in claim 6 , wherein said lubrication layer has a thickness smaller than 18 angstroms.