| 摘要 |
PROBLEM TO BE SOLVED: To prevent a lubricant from scattering because of high-speed rotation for a long time under high temperatures and high humidity by including two kinds of perfluoropolyether of different structures each having an average- number molecular weight in a specific range into a lubrication layer set continuously with a recording layer and a protecting layer on a nonmagnetic substrate. SOLUTION: The recording medium includes in a lubrication layer a perfluoropolyether: PFPT (I) expressed by a formula I and having an average- number molecular weight exceeding 5000 and not larger than 10000, and a perfluoropolyether: PFPT (II) expressed by a formula II and having an average- number molecular weight of 500-10000. In the formulae, (m) is an integer of 1-4 and (n) is an integer. The A in the formula II is an aromatic cycle with a hydrophilic group. The A is preferably a phenyl group with a hydrophilic group, particularly a group expressed by a formula III. A weight ratio is preferably set to be PFPT (I): PFPT (II)=1:20-20:1, and a film thickness of the lubrication layer is preferably set to be 0.1-10 nm. With no lubricant scattered, no stiction brought about when the medium is left for a long time after rotated at high speed.
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