An experimental study of hard-transition peakshifts through the overwrite spectra

Abstract

We have developed a frequency-domain method for the measurement of hard-transition peakshifts, using the intensities of spectral peaks as measured from a spectrum analyser. We consider the conventional overwrite environment, where a lower-frequency old CW(Continuous-Wave) pattern is overwritten by a higher-frequency new CW pattern. We then define a new overwrite parameter(OWQ) which can be shown from theory1 to relate in a simple manner to the hard-transition peakshift and shape-broadening effects. To study the validity of this approach, we have performed time- and frequency-domain measurements over a wide range of writeability conditions for thin-film inductive heads on both a thin and a thick metal-film disk. Results show that, for the thin disk, the frequency-domain results agree very well with the time-domain results. For the thick disk, the hard-transition shape-broadening effect seems more significant, introducing some errors to the frequency-domain method. Even in this case, however, the frequency-domain method still yields hard-transition peakshift results that are accurate to within 20%. © 1988 IEEE