Patent ID: 7833641

Claim:
A magnetic disk having a magnetic layer, a carbon-based protective layer, and a lubricating layer over a substrate, wherein: the magnetic disk is adapted to be mounted in a magnetic disk apparatus of a load unload system having a magnetic head flying height of 10 nm or less, and the lubricating layer contains a phosphazene compound represented by a general formula (I), the phosphazene compound having a phosphazene ring (in the formula, at least one of R 1 to R 6 is a group having a perfluoropolyether main chain represented by —(O—C 2 F 4 )m-(O—CF 2 )n- (m and n are each an integer of 1 or more) and at least two carboxyl groups in the perfluoropolyether main chain, and the remaining of R 1 to R 6 are respectively fluorine-containing groups, and three or more carboxyl groups are present in one molecule of the phosphazene compound).