Using partial erasure measurements, the depth up to which the head fie
ld is able to switch the magnetization in conventional particulate tap
es can be determined. For metal evaporated tape, this experiment shows
that the magnetization is not uniform throughout the magnetic layer.
For a single layered metal evaporated tape with a total thickness of 2
00nm, a layer with a thickness of about 55nm near the top surface is e
stimated to have a magnetization 50% higher than the mean value,