Comparison of thin film and ring heads for perpendicular recording

A self-consistent computer simulation model has been developed to study the write process of perpendicular recording with a single layer recording medium. The calculation shows that recording with a thin film head gives a significantly less write spacing loss than with a ring head. In contact, recording with either a thin film head or a ring head produces sharp transitions with high overshoot. The thin film head write spacing loss is approximately spacing independent with an averaged value of -26dB per unit change of d/λ. The ring head write spacing loss is very spacing dependent with a value of -120dB per unit change of d/λ at small spacings. For a typical head-medium spacing in rigid disk application, a 3.5dB difference in the rms voltage spectrum occurs between the two kinds of recording at a wavelength equal to twice the gap-length; the peak of the isolated voltage pulse is 2.9dB higher for recording with a thin film head than with a ring head.