Soft error rate dependence on MrT for thin film media

A study has been conducted to determine the variation of soft error rate, SER, as a function of the product between remanent magnetization and thickness, MrT, for thin film media with CoPtCr magnetic layers of three different compositions. Soft error rate as well as macromagnetic characteristics of the three sets of disks were analyzed. The soft error rate, measured at linear densities varying from 90 to 130 kBPI with a magnetoresistive head, showed a minimum for MrT values ranging between 0.6 and 0.7 memu/cm², depending on the alloy used. For values of MrT smaller than the ones mentioned above, the soft error rate quickly increased for all the magnetic layers examined because of very low coercivity, while for larger values of MrT the level of degradation, due to drop in resolution and poor overwrite, varied depending on the characteristics of the film. It was also found that, at linear densities approaching 130 kBPI the log SER improved up to 5 orders when high coercivity alloys were used, while at lower linear densities it was possible to obtain smaller error rates within a certain MrT range