Patent ID: 6780503
Filing Date: 2004-08-24
Classification: G11B,Y10T

Abstract:
A magnetic recording medium comprising:a nonmagnetic support; and at least one magnetic layer comprising a ferromagnetic hexagonal ferrite powder and a binder, wherein the magnetic layer comprises diamond particles having an average particle size of 0.03 to 0.5 &mgr;m in a ratio of 0.1 to 5% by weight to the ferromagnetic hexagonal ferrite powder, the ferrite hexagonal ferrite powder has an average tabular diameter of 5 to 40 nm, and the binder is at least one of: (i) a binder comprising from 0.2 to 0.7 meq/g of at least one polar group selected from â€”SO3M, â€”OSO3M, â€”PO(OM)2, â€”OPO(OM)2 and â€”COOM, wherein M represents a hydrogen atom, an alkali metal or ammonium, and (ii) a binder comprising from 0.5 to 5 meq/g of at least one polar group selected from â€”CONR1R2, â€”NR1R2 and â€”N+R1R2R3 wherein R1, R2 and R3 each independently represents a hydrogen atom or an alkyl group.