Tape erase bands measured by MFM compared to MR head cross erase band responses

Abstract

The erase bands written on tape by heads with CoZrTa and permalloy poles were compared by using MFM techniques and by measuring MR head responses as the heads were moved in the cross track direction. Measurements were made under conditions of both the top and bottom poles trailing, as well as for two different overwrite frequencies (2f and 4f). From both methods, it was found that the erase band is more dependent on which pole is trailing, than on the write head pole materials. In all cases, the top pole trailing (TPT) case yields narrower erase bands than the bottom pole trailing (BPT) case. The boundaries of the erase band become less distinct when the overwrite frequency increases. The phase difference between adjacent tracks does not play a big role in the case of BPT, but does matter in the case of TPT. The cross erase band profile demonstrates that the transport system is stable enough, and that this method to measure the erase band is feasible in the presence of tape motion.