therefore the protection film 6 is almost flat the lubricating film 7 is composed of phlorocarbon and formed in the thickness of 2 nm on the protection film 6 the magnetic memory medium of the present invention has been manufactured using the material and method explained above as a result level difference between the land and groove at the surface is controlled to 2 to 3 nm 0064 fig1 illustrates the relationship between the laser power in the smoothing process and the level difference between the land and groove of the smoothing thin film tec when the laser power is 0 to 1 mw the tec film does not fuse and therefore the level difference does not almost change when the laser power is raised to 1 5 mw the tec film starts to fuse and flows into the groove thereby reducing the level difference when the laser power becomes 2 5 mw or higher the tec film on the land almost moves to the groove and thereby level difference is reduced up to 2 nm 0065 fig1 illustrates an apparatus for detecting a crash of a disc medium and a head comprising an air spindle 30 for rotating a medium to be tested a suspension 32 for supporting the head an ae sensor 32 for sensing.