A Surface Roughness Evaluation Method of Magnetic Recording Media

It is well known that recording and reproduce characteristics at short wavelengths are influenced by the surface roughness of the magnetic recording medium. The surface roughness is usually measured by an apparatus designed for the purpose, with the result expressed in terms of one of several indexes--RMS, R^a or Rmax. Since these indexes are defined for general use, they are not always suitable for evaluation of medium surface roughness. We therefore studied a new index, using computer simulations involving the distance between the medium surface and the head gap. In simulations, the head was scanned over the medium surface and the distance calculated using a spacing loss coefficient. The new index is useful for evaluating the surface roughness of contact recording media, especially when comparing the roughnesses of different kinds of media.