Magnetic recording medium comprising a glass substrate of controlled surface roughness and a magnetic thin film layer of gamma Fe2O3

摘要

A magnetic recording disk comprising a rigid substrate and a magnetic layer of the continuous thin film type predominantly composed of gamma -Fe2O3 shows high durability, especially CSS durability when the magnetic layer has specific peak area ratios in an X-ray diffraction chart thereof, the surface roughness of the substrate and medium surface is controlled to desired ranges, and a lubricating film of a perfluoro derivative of poly(n-propylene oxide) with a specific molecular weight is used. Reliable recording/reproduction can be conducted on the magnetic recording disk using a flying magnetic head.