Lubricant and magnetic recording medium using the same

A magnetic recording medium comprising a substrate having thereon a magnetic layer and a lubricant layer wherein said lubricant is provided on the outermost layer at a thickness of at most about 20 .ANG. and is a compound which is devoid polar groups at the terminals of its molecule and which is represented by the following formula (I):

• R.sub.1 --(Y--R.sub.2).sub.k --Y--R.sub.1 (I)
• wherein Y is selected from the group consisting of the divalent residue of a carboxyl group-containing compound, the divalent residue of an isocyanate group-containing compound and the divalent residue of a hydroxyl group-containing compound, and all Y groups in formula (I) may be the same or different when k is 2 or more;
• R.sub.1 represents a perfluoropolyether chain comprising a repeating unit of (C.sub.a F.sub.2a O).sub.b wherein a is 1, 2 or 3, and b is at least 2, which is terminated by --CF.sub.3 and has a number average molecular weight of about 400 to 10,000, and both R.sub.1 groups in formula (I) may be the same or different;
• R.sub.2 represents a perfluoropolyether chain comprising a repeating unit of C.sub.c F.sub.2c O).sub.d wherein c is 1, 2 or 3, and d is an integer of at least 1 and all R.sub.2 groups in formula (I) may be the same or different when k is 2 or more;
• and
• k is an integer of at least 1.